diff --git a/contrib/libtests/makepng.c b/contrib/libtests/makepng.c
index 9dff048..e58a61d 100644
--- a/contrib/libtests/makepng.c
+++ b/contrib/libtests/makepng.c
@@ -950,7 +950,7 @@
             int passes = 1;
 #        endif /* !WRITE_INTERLACING */
          int pass;
-         png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+         size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
 
          row = malloc(rowbytes);
 
@@ -1094,7 +1094,7 @@
    return 0;
 }
 
-static png_size_t
+static size_t
 load_fake(png_charp param, png_bytepp profile)
 {
    char *endptr = NULL;
@@ -1164,7 +1164,7 @@
    {
       case '<':
          {
-            png_size_t filelen = load_file(params[1]+1, &profile);
+            size_t filelen = load_file(params[1]+1, &profile);
             if (filelen > 0xfffffffc) /* Maximum profile length */
             {
                fprintf(stderr, "%s: file too long (%lu) for an ICC profile\n",
@@ -1179,7 +1179,7 @@
       case '0': case '1': case '2': case '3': case '4':
       case '5': case '6': case '7': case '8': case '9':
          {
-            png_size_t fake_len = load_fake(params[1], &profile);
+            size_t fake_len = load_fake(params[1], &profile);
 
             if (fake_len > 0) /* else a simple parameter */
             {
@@ -1274,7 +1274,7 @@
       case '5': case '6': case '7': case '8': case '9':
          {
             png_bytep data = NULL;
-            png_size_t fake_len = load_fake(param, &data);
+            size_t fake_len = load_fake(param, &data);
 
             if (fake_len > 0) /* else a simple parameter */
             {
diff --git a/contrib/libtests/pngimage.c b/contrib/libtests/pngimage.c
index bd8dac6..998d58c 100644
--- a/contrib/libtests/pngimage.c
+++ b/contrib/libtests/pngimage.c
@@ -551,7 +551,7 @@
    png_structp    original_pp;       /* used on the original read */
    png_infop      original_ip;       /* set by the original read */
 
-   png_size_t     original_rowbytes; /* of the original rows: */
+   size_t         original_rowbytes; /* of the original rows: */
    png_bytepp     original_rows;     /* from the original read */
 
    /* Original chunks valid */
@@ -807,7 +807,7 @@
 
 static void
 buffer_read(struct display *dp, struct buffer *bp, png_bytep data,
-   png_size_t size)
+   size_t size)
 {
    struct buffer_list *last = bp->current;
    size_t read_count = bp->read_count;
@@ -855,7 +855,7 @@
 }
 
 static void PNGCBAPI
-read_function(png_structp pp, png_bytep data, png_size_t size)
+read_function(png_structp pp, png_bytep data, size_t size)
 {
    buffer_read(get_dp(pp), get_buffer(pp), data, size);
 }
@@ -1267,7 +1267,7 @@
 #ifdef PNG_WRITE_PNG_SUPPORTED
 static void
 buffer_write(struct display *dp, struct buffer *buffer, png_bytep data,
-   png_size_t size)
+   size_t size)
    /* Generic write function used both from the write callback provided to
     * libpng and from the generic read code.
     */
@@ -1311,7 +1311,7 @@
 }
 
 static void PNGCBAPI
-write_function(png_structp pp, png_bytep data, png_size_t size)
+write_function(png_structp pp, png_bytep data, size_t size)
 {
    buffer_write(get_dp(pp), get_buffer(pp), data, size);
 }
diff --git a/contrib/libtests/pngstest.c b/contrib/libtests/pngstest.c
index e7e03e8..74c8d10 100644
--- a/contrib/libtests/pngstest.c
+++ b/contrib/libtests/pngstest.c
@@ -578,11 +578,11 @@
    int         stride_extra;
    FILE       *input_file;
    png_voidp   input_memory;
-   png_size_t  input_memory_size;
+   size_t      input_memory_size;
    png_bytep   buffer;
    ptrdiff_t   stride;
-   png_size_t  bufsize;
-   png_size_t  allocsize;
+   size_t      bufsize;
+   size_t      allocsize;
    char        tmpfile_name[32];
    png_uint_16 colormap[256*4];
 }
@@ -665,7 +665,7 @@
 static void
 allocbuffer(Image *image)
 {
-   png_size_t size = PNG_IMAGE_BUFFER_SIZE(image->image, image->stride);
+   size_t size = PNG_IMAGE_BUFFER_SIZE(image->image, image->stride);
 
    if (size+32 > image->bufsize)
    {
diff --git a/contrib/libtests/pngvalid.c b/contrib/libtests/pngvalid.c
index 3fdc002..e66f2fa 100644
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -711,7 +711,7 @@
    unsigned int            IDAT_bits; /* Number of bits in IDAT size */
    png_uint_32             IDAT_size; /* Total size of IDAT data */
    png_uint_32             id;        /* must be correct (see FILEID) */
-   png_size_t              datacount; /* In this (the last) buffer */
+   size_t                  datacount; /* In this (the last) buffer */
    png_store_buffer        data;      /* Last buffer in file */
    int                     npalette;  /* Number of entries in palette */
    store_palette_entry*    palette;   /* May be NULL */
@@ -777,10 +777,10 @@
    png_infop          piread;
    png_store_file*    current;  /* Set when reading */
    png_store_buffer*  next;     /* Set when reading */
-   png_size_t         readpos;  /* Position in *next */
+   size_t             readpos;  /* Position in *next */
    png_byte*          image;    /* Buffer for reading interlaced images */
-   png_size_t         cb_image; /* Size of this buffer */
-   png_size_t         cb_row;   /* Row size of the image(s) */
+   size_t             cb_image; /* Size of this buffer */
+   size_t             cb_row;   /* Row size of the image(s) */
    uLong              IDAT_crc;
    png_uint_32        IDAT_len; /* Used when re-chunking IDAT chunks */
    png_uint_32        IDAT_pos; /* Used when re-chunking IDAT chunks */
@@ -791,7 +791,7 @@
    png_store_file*    saved;
    png_structp        pwrite;   /* Used when writing a new file */
    png_infop          piwrite;
-   png_size_t         writepos; /* Position in .new */
+   size_t             writepos; /* Position in .new */
    char               wname[FILE_NAME_SIZE];
    png_store_buffer   new;      /* The end of the new PNG file being written. */
    store_pool         write_memory_pool;
@@ -1125,7 +1125,7 @@
 store_image_row(const png_store* ps, png_const_structp pp, int nImage,
    png_uint_32 y)
 {
-   png_size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
+   size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
 
    if (ps->image == NULL)
       png_error(pp, "no allocated image");
@@ -1160,9 +1160,9 @@
 
 static void
 store_ensure_image(png_store *ps, png_const_structp pp, int nImages,
-   png_size_t cbRow, png_uint_32 cRows)
+   size_t cbRow, png_uint_32 cRows)
 {
-   png_size_t cb = nImages * cRows * (cbRow + 5);
+   size_t cb = nImages * cRows * (cbRow + 5);
 
    if (ps->cb_image < cb)
    {
@@ -1234,7 +1234,7 @@
       png_error(pp, "image overwrite");
    else
    {
-      png_size_t cbRow = ps->cb_row;
+      size_t cbRow = ps->cb_row;
       png_uint_32 rows = ps->image_h;
 
       image += iImage * (cbRow+5) * ps->image_h;
@@ -1278,7 +1278,7 @@
 }
 
 static void PNGCBAPI
-store_write(png_structp ppIn, png_bytep pb, png_size_t st)
+store_write(png_structp ppIn, png_bytep pb, size_t st)
 {
    png_const_structp pp = ppIn;
    png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
@@ -1346,13 +1346,13 @@
 
       else /* chunkpos >= 8 */
       {
-         png_size_t cb = st;
+         size_t cb = st;
 
          if (cb > STORE_BUFFER_SIZE - writepos)
             cb = STORE_BUFFER_SIZE - writepos;
 
          if (cb  > chunklen - chunkpos/* bytes left in chunk*/)
-            cb = (png_size_t)/*SAFE*/(chunklen - chunkpos);
+            cb = (size_t)/*SAFE*/(chunklen - chunkpos);
 
          memcpy(ps->new.buffer + writepos, pb, cb);
          chunkpos += (png_uint_32)/*SAFE*/cb;
@@ -1440,7 +1440,7 @@
  * during progressive read, where the io_ptr is set internally by libpng.
  */
 static void
-store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
+store_read_imp(png_store *ps, png_bytep pb, size_t st)
 {
    if (ps->current == NULL || ps->next == NULL)
       png_error(ps->pread, "store state damaged");
@@ -1463,14 +1463,13 @@
    }
 }
 
-static png_size_t
-store_read_chunk(png_store *ps, png_bytep pb, const png_size_t max,
-      const png_size_t min)
+static size_t
+store_read_chunk(png_store *ps, png_bytep pb, size_t max, size_t min)
 {
    png_uint_32 chunklen = ps->chunklen;
    png_uint_32 chunktype = ps->chunktype;
    png_uint_32 chunkpos = ps->chunkpos;
-   png_size_t st = max;
+   size_t st = max;
 
    if (st > 0) do
    {
@@ -1601,8 +1600,8 @@
 
                store_read_imp(ps, pb, avail);
                ps->IDAT_crc = crc32(ps->IDAT_crc, pb, avail);
-               pb += (png_size_t)/*SAFE*/avail;
-               st -= (png_size_t)/*SAFE*/avail;
+               pb += (size_t)/*SAFE*/avail;
+               st -= (size_t)/*SAFE*/avail;
                chunkpos += (png_uint_32)/*SAFE*/avail;
                IDAT_size -= (png_uint_32)/*SAFE*/avail;
                IDAT_pos += (png_uint_32)/*SAFE*/avail;
@@ -1669,10 +1668,10 @@
 
          else /* Return chunk bytes, including the CRC */
          {
-            png_size_t avail = st;
+            size_t avail = st;
 
             if (avail > chunklen - chunkpos)
-               avail = (png_size_t)/*SAFE*/(chunklen - chunkpos);
+               avail = (size_t)/*SAFE*/(chunklen - chunkpos);
 
             store_read_imp(ps, pb, avail);
             pb += avail;
@@ -1698,7 +1697,7 @@
 }
 
 static void PNGCBAPI
-store_read(png_structp ppIn, png_bytep pb, png_size_t st)
+store_read(png_structp ppIn, png_bytep pb, size_t st)
 {
    png_const_structp pp = ppIn;
    png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
@@ -1724,7 +1723,7 @@
    while (store_read_buffer_avail(ps) > 0)
    {
       static png_uint_32 noise = 2;
-      png_size_t cb;
+      size_t cb;
       png_byte buffer[512];
 
       /* Generate 15 more bits of stuff: */
@@ -2991,7 +2990,7 @@
  * png_struct.
  */
 static void
-modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
+modifier_read_imp(png_modifier *pm, png_bytep pb, size_t st)
 {
    while (st > 0)
    {
@@ -3137,7 +3136,7 @@
              */
             if (len+12 <= sizeof pm->buffer)
             {
-               png_size_t s = len+12-pm->buffer_count;
+               size_t s = len+12-pm->buffer_count;
                store_read_chunk(&pm->this, pm->buffer+pm->buffer_count, s, s);
                pm->buffer_count = len+12;
 
@@ -3196,7 +3195,7 @@
 
 /* The callback: */
 static void PNGCBAPI
-modifier_read(png_structp ppIn, png_bytep pb, png_size_t st)
+modifier_read(png_structp ppIn, png_bytep pb, size_t st)
 {
    png_const_structp pp = ppIn;
    png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
@@ -3226,7 +3225,7 @@
    for (;;)
    {
       static png_uint_32 noise = 1;
-      png_size_t cb, cbAvail;
+      size_t cb, cbAvail;
       png_byte buffer[512];
 
       /* Generate 15 more bits of stuff: */
diff --git a/contrib/libtests/readpng.c b/contrib/libtests/readpng.c
index 3336d4e..60a2d46 100644
--- a/contrib/libtests/readpng.c
+++ b/contrib/libtests/readpng.c
@@ -60,7 +60,7 @@
    png_read_info(png_ptr, info_ptr);
 
    {
-      png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+      size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
 
       /* Failure to initialize these is harmless */
       row = malloc(rowbytes);
diff --git a/contrib/libtests/tarith.c b/contrib/libtests/tarith.c
index aea2112..c95226f 100644
--- a/contrib/libtests/tarith.c
+++ b/contrib/libtests/tarith.c
@@ -108,7 +108,7 @@
 
    do
    {
-      png_size_t index;
+      size_t index;
       int state, failed = 0;
       char buffer[64];
 
@@ -329,7 +329,7 @@
 {
    /* Test this character (ch) to ensure the parser does the correct thing.
     */
-   png_size_t index = 0;
+   size_t index = 0;
    const char test = (char)ch;
    const int number_is_valid = png_check_fp_number(&test, 1, &c.state, &index);
    const int character_accepted = (index == 1);
diff --git a/contrib/libtests/timepng.c b/contrib/libtests/timepng.c
index 3bcfde5..23d8b17 100644
--- a/contrib/libtests/timepng.c
+++ b/contrib/libtests/timepng.c
@@ -65,7 +65,7 @@
 }  io_data;
 
 static PNG_CALLBACK(void, read_and_copy,
-      (png_structp png_ptr, png_bytep buffer, png_size_t cb))
+      (png_structp png_ptr, png_bytep buffer, size_t cb))
 {
    io_data *io = (io_data*)png_get_io_ptr(png_ptr);
 
@@ -100,7 +100,7 @@
    png_read_info(png_ptr, info_ptr);
 
    {
-      png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+      size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
 
       row = voidcast(png_bytep,malloc(rowbytes));
       display = voidcast(png_bytep,malloc(rowbytes));
diff --git a/contrib/oss-fuzz/libpng_read_fuzzer.cc b/contrib/oss-fuzz/libpng_read_fuzzer.cc
index 32f0af2..74b29ec 100644
--- a/contrib/oss-fuzz/libpng_read_fuzzer.cc
+++ b/contrib/oss-fuzz/libpng_read_fuzzer.cc
@@ -68,7 +68,7 @@
   }
 };
 
-void user_read_data(png_structp png_ptr, png_bytep data, png_size_t length) {
+void user_read_data(png_structp png_ptr, png_bytep data, size_t length) {
   BufState* buf_state = static_cast<BufState*>(png_get_io_ptr(png_ptr));
   if (length > buf_state->bytes_left) {
     png_error(png_ptr, "read error");
diff --git a/contrib/tools/pngcp.c b/contrib/tools/pngcp.c
index 2f6ea65..f6a0d50 100644
--- a/contrib/tools/pngcp.c
+++ b/contrib/tools/pngcp.c
@@ -1725,7 +1725,7 @@
 }
 
 static void PNGCBAPI
-read_function(png_structp pp, png_bytep data, png_size_t size)
+read_function(png_structp pp, png_bytep data, size_t size)
 {
    struct display *dp = get_dp(pp);
 
@@ -1881,7 +1881,7 @@
 }
 
 static void PNGCBAPI
-write_function(png_structp pp, png_bytep data, png_size_t size)
+write_function(png_structp pp, png_bytep data, size_t size)
 {
    struct display *dp = get_dp(pp);
 
diff --git a/contrib/visupng/PngFile.c b/contrib/visupng/PngFile.c
index d46318f..cf943f3 100644
--- a/contrib/visupng/PngFile.c
+++ b/contrib/visupng/PngFile.c
@@ -410,15 +410,14 @@
 #ifndef PNG_STDIO_SUPPORTED
 
 static void
-png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
+png_read_data(png_structp png_ptr, png_bytep data, size_t length)
 {
-   png_size_t check;
+   size_t check;
 
-   /* fread() returns 0 on error, so it is OK to store this in a png_size_t
+   /* fread() returns 0 on error, so it is OK to store this in a size_t
     * instead of an int, which is what fread() actually returns.
     */
-   check = (png_size_t)fread(data, (png_size_t)1, length,
-      (FILE *)png_ptr->io_ptr);
+   check = fread(data, 1, length, (FILE *)png_ptr->io_ptr);
 
    if (check != length)
    {
@@ -427,7 +426,7 @@
 }
 
 static void
-png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+png_write_data(png_structp png_ptr, png_bytep data, size_t length)
 {
    png_uint_32 check;
 
diff --git a/contrib/visupng/PngFile.h b/contrib/visupng/PngFile.h
index 474426c..1b7b9be 100644
--- a/contrib/visupng/PngFile.h
+++ b/contrib/visupng/PngFile.h
@@ -23,8 +23,8 @@
                    int iWidth, int iHeight, png_color BkgColor);
 
 #ifndef PNG_STDIO_SUPPORTED
-static void png_read_data(png_structp png_ptr, png_bytep data, png_size_t length);
-static void png_write_data(png_structp png_ptr, png_bytep data, png_size_t length);
+static void png_read_data(png_structp png_ptr, png_bytep data, size_t length);
+static void png_write_data(png_structp png_ptr, png_bytep data, size_t length);
 static void png_flush(png_structp png_ptr);
 #endif
 
diff --git a/example.c b/example.c
index 99d2f05..94fe99d 100644
--- a/example.c
+++ b/example.c
@@ -257,7 +257,7 @@
    /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
       Return nonzero (true) if they match */
 
-   return(!png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK));
+   return(!png_sig_cmp(buf, 0, PNG_BYTES_TO_CHECK));
 }
 
 /* Read a PNG file.  You may want to return an error code if the read
diff --git a/intel/filter_sse2_intrinsics.c b/intel/filter_sse2_intrinsics.c
index 5e8553f..ef1fc7d 100644
--- a/intel/filter_sse2_intrinsics.c
+++ b/intel/filter_sse2_intrinsics.c
@@ -71,7 +71,7 @@
     * There is no pixel to the left of the first pixel.  It's encoded directly.
     * That works with our main loop if we just say that left pixel was zero.
     */
-   png_size_t rb;
+   size_t rb;
 
    __m128i a, d = _mm_setzero_si128();
 
@@ -104,7 +104,7 @@
     * There is no pixel to the left of the first pixel.  It's encoded directly.
     * That works with our main loop if we just say that left pixel was zero.
     */
-   png_size_t rb;
+   size_t rb;
 
    __m128i a, d = _mm_setzero_si128();
 
@@ -131,7 +131,7 @@
     * perfectly with our loop if we make sure a starts at zero.
     */
 
-   png_size_t rb;
+   size_t rb;
 
    const __m128i zero = _mm_setzero_si128();
 
@@ -185,7 +185,7 @@
     * predicted to be half of the pixel above it.  So again, this works
     * perfectly with our loop if we make sure a starts at zero.
     */
-   png_size_t rb;
+   size_t rb;
    const __m128i zero = _mm_setzero_si128();
    __m128i    b;
    __m128i a, d = zero;
@@ -257,7 +257,7 @@
     * Here we zero b and d, which become c and a respectively at the start of
     * the loop.
     */
-   png_size_t rb;
+   size_t rb;
    const __m128i zero = _mm_setzero_si128();
    __m128i c, b = zero,
            a, d = zero;
@@ -356,7 +356,7 @@
     * Here we zero b and d, which become c and a respectively at the start of
     * the loop.
     */
-   png_size_t rb;
+   size_t rb;
    const __m128i zero = _mm_setzero_si128();
    __m128i pa,pb,pc,smallest,nearest;
    __m128i c, b = zero,
diff --git a/libpng-manual.txt b/libpng-manual.txt
index 081a1cb..ef8d601 100644
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -503,7 +503,7 @@
 
            png_byte name[5];
            png_byte *data;
-           png_size_t size;
+           size_t size;
 
        /* Note that libpng has already taken care of
           the CRC handling */
@@ -4102,7 +4102,7 @@
       The PNG header is read from the stdio FILE object.
 
    int png_image_begin_read_from_memory(png_imagep image,
-      png_const_voidp memory, png_size_t size)
+      png_const_voidp memory, size_t size)
 
       The PNG header is read from the given memory buffer.
 
@@ -4255,10 +4255,10 @@
 The replacement I/O functions must have prototypes as follows:
 
     void user_read_data(png_structp png_ptr,
-        png_bytep data, png_size_t length);
+        png_bytep data, size_t length);
 
     void user_write_data(png_structp png_ptr,
-        png_bytep data, png_size_t length);
+        png_bytep data, size_t length);
 
     void user_flush_data(png_structp png_ptr);
 
@@ -4784,7 +4784,7 @@
 the process.
 
 We changed the prototypes of png_get_compression_buffer_size() and
-png_set_compression_buffer_size() to work with png_size_t instead of
+png_set_compression_buffer_size() to work with size_t instead of
 png_uint_32.
 
 Support for numbered error messages was removed by default, since we
diff --git a/libpng.3 b/libpng.3
index 4827d80..cdc3731 100644
--- a/libpng.3
+++ b/libpng.3
@@ -225,7 +225,7 @@
 
 \fBint png_image_begin_read_from_stdio (png_imagep \fP\fIimage\fP\fB, FILE* \fIfile\fP\fB);\fP
 
-\fBint, png_image_begin_read_from_memory (png_imagep \fP\fIimage\fP\fB, png_const_voidp \fP\fImemory\fP\fB, png_size_t \fIsize\fP\fB);\fP
+\fBint, png_image_begin_read_from_memory (png_imagep \fP\fIimage\fP\fB, png_const_voidp \fP\fImemory\fP\fB, size_t \fIsize\fP\fB);\fP
 
 \fBint png_image_finish_read (png_imagep \fP\fIimage\fP\fB, png_colorp \fP\fIbackground\fP\fB, void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP
 
@@ -237,7 +237,7 @@
 
 \fBint png_image_write_to_stdio (png_imagep \fP\fIimage\fP\fB, FILE \fP\fI*file\fP\fB, int \fP\fIconvert_to_8_bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap)\fP\fB);\fP
 
-\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, png_size_t \fIpng_info_struct_size\fP\fB);\fP
+\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, size_t \fIpng_info_struct_size\fP\fB);\fP
 
 \fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP
 
@@ -251,9 +251,9 @@
 
 \fBpng_uint_32 png_permit_mng_features (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fImng_features_permitted\fP\fB);\fP
 
-\fBvoid png_process_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_size\fP\fB);\fP
+\fBvoid png_process_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, size_t \fIbuffer_size\fP\fB);\fP
 
-\fBpng_size_t png_process_data_pause \fP\fI(png_structp\fP\fB, int \fIsave\fP\fB);\fP
+\fBsize_t png_process_data_pause \fP\fI(png_structp\fP\fB, int \fIsave\fP\fB);\fP
 
 \fBpng_uint_32 png_process_data_skip \fI(png_structp\fP\fB);\fP
 
@@ -475,15 +475,15 @@
 
 \fBvoid png_set_write_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIwrite_user_transform_fn\fP\fB);\fP
 
-\fBint png_sig_cmp (png_bytep \fP\fIsig\fP\fB, png_size_t \fP\fIstart\fP\fB, png_size_t \fInum_to_check\fP\fB);\fP
+\fBint png_sig_cmp (png_bytep \fP\fIsig\fP\fB, size_t \fP\fIstart\fP\fB, size_t \fInum_to_check\fP\fB);\fP
 
 \fBvoid png_start_read_image (png_structp \fIpng_ptr\fP\fB);\fP
 
 \fBvoid png_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
 
-\fBvoid png_write_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
+\fBvoid png_write_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_bytep \fP\fIdata\fP\fB, size_t \fIlength\fP\fB);\fP
 
-\fBvoid png_write_chunk_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
+\fBvoid png_write_chunk_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, size_t \fIlength\fP\fB);\fP
 
 \fBvoid png_write_chunk_end (png_structp \fIpng_ptr\fP\fB);\fP
 
@@ -1021,7 +1021,7 @@
 
            png_byte name[5];
            png_byte *data;
-           png_size_t size;
+           size_t size;
 
        /* Note that libpng has already taken care of
           the CRC handling */
@@ -4620,7 +4620,7 @@
       The PNG header is read from the stdio FILE object.
 
    int png_image_begin_read_from_memory(png_imagep image,
-      png_const_voidp memory, png_size_t size)
+      png_const_voidp memory, size_t size)
 
       The PNG header is read from the given memory buffer.
 
@@ -4773,10 +4773,10 @@
 The replacement I/O functions must have prototypes as follows:
 
     void user_read_data(png_structp png_ptr,
-        png_bytep data, png_size_t length);
+        png_bytep data, size_t length);
 
     void user_write_data(png_structp png_ptr,
-        png_bytep data, png_size_t length);
+        png_bytep data, size_t length);
 
     void user_flush_data(png_structp png_ptr);
 
@@ -5302,7 +5302,7 @@
 the process.
 
 We changed the prototypes of png_get_compression_buffer_size() and
-png_set_compression_buffer_size() to work with png_size_t instead of
+png_set_compression_buffer_size() to work with size_t instead of
 png_uint_32.
 
 Support for numbered error messages was removed by default, since we
diff --git a/mips/filter_msa_intrinsics.c b/mips/filter_msa_intrinsics.c
index 943bb3d..5705628 100644
--- a/mips/filter_msa_intrinsics.c
+++ b/mips/filter_msa_intrinsics.c
@@ -366,8 +366,8 @@
 void png_read_filter_row_up_msa(png_row_infop row_info, png_bytep row,
                                 png_const_bytep prev_row)
 {
-   png_size_t i, cnt, cnt16, cnt32;
-   png_size_t istop = row_info->rowbytes;
+   size_t i, cnt, cnt16, cnt32;
+   size_t istop = row_info->rowbytes;
    png_bytep rp = row;
    png_const_bytep pp = prev_row;
    v16u8 src0, src1, src2, src3, src4, src5, src6, src7;
@@ -457,8 +457,8 @@
 void png_read_filter_row_sub4_msa(png_row_infop row_info, png_bytep row,
                                   png_const_bytep prev_row)
 {
-   png_size_t count;
-   png_size_t istop = row_info->rowbytes;
+   size_t count;
+   size_t istop = row_info->rowbytes;
    png_bytep src = row;
    png_bytep nxt = row + 4;
    int32_t inp0;
@@ -496,8 +496,8 @@
 void png_read_filter_row_sub3_msa(png_row_infop row_info, png_bytep row,
                                   png_const_bytep prev_row)
 {
-   png_size_t count;
-   png_size_t istop = row_info->rowbytes;
+   size_t count;
+   size_t istop = row_info->rowbytes;
    png_bytep src = row;
    png_bytep nxt = row + 3;
    int64_t out0;
@@ -541,11 +541,11 @@
 void png_read_filter_row_avg4_msa(png_row_infop row_info, png_bytep row,
                                   png_const_bytep prev_row)
 {
-   png_size_t i;
+   size_t i;
    png_bytep src = row;
    png_bytep nxt = row;
    png_const_bytep pp = prev_row;
-   png_size_t istop = row_info->rowbytes - 4;
+   size_t istop = row_info->rowbytes - 4;
    int32_t inp0, inp1, out0;
    v16u8 src0, src1, src2, src3, src4, src5, src6, src7, src8, src9, dst0, dst1;
    v16u8 zero = { 0 };
@@ -592,11 +592,11 @@
 void png_read_filter_row_avg3_msa(png_row_infop row_info, png_bytep row,
                                   png_const_bytep prev_row)
 {
-   png_size_t i;
+   size_t i;
    png_bytep src = row;
    png_bytep nxt = row;
    png_const_bytep pp = prev_row;
-   png_size_t istop = row_info->rowbytes - 3;
+   size_t istop = row_info->rowbytes - 3;
    int64_t out0;
    int32_t inp0, inp1, out1;
    int16_t out2;
diff --git a/png.c b/png.c
index b556bb4..f6cfe9e 100644
--- a/png.c
+++ b/png.c
@@ -71,7 +71,7 @@
  * PNG signature (this is the same behavior as strcmp, memcmp, etc).
  */
 int PNGAPI
-png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
+png_sig_cmp(png_const_bytep sig, size_t start, size_t num_to_check)
 {
    png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
 
@@ -136,7 +136,7 @@
  * trouble of calculating it.
  */
 void /* PRIVATE */
-png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)
+png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, size_t length)
 {
    int need_crc = 1;
 
@@ -421,7 +421,7 @@
  * those cases where it does anything other than a memset.
  */
 PNG_FUNCTION(void,PNGAPI
-png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size),
+png_info_init_3,(png_infopp ptr_ptr, size_t png_info_struct_size),
     PNG_DEPRECATED)
 {
    png_inforp info_ptr = *ptr_ptr;
@@ -2715,11 +2715,11 @@
 #define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY))
 
 int /* PRIVATE */
-png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
+png_check_fp_number(png_const_charp string, size_t size, int *statep,
     png_size_tp whereami)
 {
    int state = *statep;
-   png_size_t i = *whereami;
+   size_t i = *whereami;
 
    while (i < size)
    {
@@ -2842,10 +2842,10 @@
 
 /* The same but for a complete string. */
 int
-png_check_fp_string(png_const_charp string, png_size_t size)
+png_check_fp_string(png_const_charp string, size_t size)
 {
    int        state=0;
-   png_size_t char_index=0;
+   size_t char_index=0;
 
    if (png_check_fp_number(string, size, &state, &char_index) != 0 &&
       (char_index == size || string[char_index] == 0))
@@ -2906,7 +2906,7 @@
 #pragma GCC diagnostic warning "-Wstrict-overflow=2"
 #endif /* GCC_STRICT_OVERFLOW */
 void /* PRIVATE */
-png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
+png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, size_t size,
     double fp, unsigned int precision)
 {
    /* We use standard functions from math.h, but not printf because
@@ -3237,7 +3237,7 @@
  */
 void /* PRIVATE */
 png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
-    png_size_t size, png_fixed_point fp)
+    size_t size, png_fixed_point fp)
 {
    /* Require space for 10 decimal digits, a decimal point, a minus sign and a
     * trailing \0, 13 characters:
diff --git a/png.h b/png.h
index 48c8fc3..0090a1b 100644
--- a/png.h
+++ b/png.h
@@ -600,8 +600,8 @@
    png_charp key;          /* keyword, 1-79 character description of "text" */
    png_charp text;         /* comment, may be an empty string (ie "")
                               or a NULL pointer */
-   png_size_t text_length; /* length of the text string */
-   png_size_t itxt_length; /* length of the itxt string */
+   size_t text_length;     /* length of the text string */
+   size_t itxt_length;     /* length of the itxt string */
    png_charp lang;         /* language code, 0-79 characters
                               or a NULL pointer */
    png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
@@ -654,7 +654,7 @@
 {
    png_byte name[5]; /* Textual chunk name with '\0' terminator */
    png_byte *data;   /* Data, should not be modified on read! */
-   png_size_t size;
+   size_t size;
 
    /* On write 'location' must be set using the flag values listed below.
     * Notice that on read it is set by libpng however the values stored have
@@ -679,7 +679,7 @@
 /* Maximum positive integer used in PNG is (2^31)-1 */
 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
-#define PNG_SIZE_MAX ((png_size_t)(-1))
+#define PNG_SIZE_MAX ((size_t)(-1))
 
 /* These are constants for fixed point values encoded in the
  * PNG specification manner (x100000)
@@ -785,7 +785,7 @@
 typedef struct png_row_info_struct
 {
    png_uint_32 width;    /* width of row */
-   png_size_t rowbytes;  /* number of bytes in row */
+   size_t rowbytes;      /* number of bytes in row */
    png_byte color_type;  /* color type of row */
    png_byte bit_depth;   /* bit depth of row */
    png_byte channels;    /* number of channels (1, 2, 3, or 4) */
@@ -804,7 +804,7 @@
  * expected to return the read data in the buffer.
  */
 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
-typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
+typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
     int));
@@ -941,8 +941,8 @@
  * signature, and non-zero otherwise.  Having num_to_check == 0 or
  * start > 7 will always fail (ie return non-zero).
  */
-PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
-    png_size_t num_to_check));
+PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start,
+    size_t num_to_check));
 
 /* Simple signature checking function.  This is the same as calling
  * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
@@ -961,11 +961,11 @@
     png_error_ptr warn_fn),
     PNG_ALLOCATED);
 
-PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
+PNG_EXPORT(6, size_t, png_get_compression_buffer_size,
     (png_const_structrp png_ptr));
 
 PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
-    png_size_t size));
+    size_t size));
 
 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
  * match up.
@@ -1018,7 +1018,7 @@
 
 /* Write a PNG chunk - size, type, (optional) data, CRC. */
 PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
-    chunk_name, png_const_bytep data, png_size_t length));
+    chunk_name, png_const_bytep data, size_t length));
 
 /* Write the start of a PNG chunk - length and chunk name. */
 PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
@@ -1026,7 +1026,7 @@
 
 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
 PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
-    png_const_bytep data, png_size_t length));
+    png_const_bytep data, size_t length));
 
 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
 PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
@@ -1040,7 +1040,7 @@
  * the API will be removed in the future.
  */
 PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
-    png_size_t png_info_struct_size), PNG_DEPRECATED);
+    size_t png_info_struct_size), PNG_DEPRECATED);
 
 /* Writes all the PNG information before the image. */
 PNG_EXPORT(20, void, png_write_info_before_PLTE,
@@ -1716,7 +1716,7 @@
 
 /* Function to be called when data becomes available */
 PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
-    png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));
+    png_inforp info_ptr, png_bytep buffer, size_t buffer_size));
 
 /* A function which may be called *only* within png_process_data to stop the
  * processing of any more data.  The function returns the number of bytes
@@ -1725,7 +1725,7 @@
  * 'save' is set to true the routine will first save all the pending data and
  * will always return 0.
  */
-PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));
+PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save));
 
 /* A function which may be called *only* outside (after) a call to
  * png_process_data.  It returns the number of bytes of data to skip in the
@@ -1870,7 +1870,7 @@
     png_const_inforp info_ptr, png_uint_32 flag));
 
 /* Returns number of bytes needed to hold a transformed row. */
-PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
+PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr,
     png_const_inforp info_ptr));
 
 #ifdef PNG_INFO_IMAGE_SUPPORTED
@@ -3020,7 +3020,7 @@
 #endif /* STDIO */
 
 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
-   png_const_voidp memory, png_size_t size));
+   png_const_voidp memory, size_t size));
    /* The PNG header is read from the given memory buffer. */
 
 PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
diff --git a/pngconf.h b/pngconf.h
index 7ef2c6b..40bc99a 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -515,8 +515,10 @@
 #  error "libpng requires an unsigned 32-bit (or more) type"
 #endif
 
-/* Prior to 1.6.0 it was possible to disable the use of size_t, 1.6.0, however,
- * requires an ISOC90 compiler and relies on consistent behavior of sizeof.
+/* Prior to 1.6.0, it was possible to disable the use of size_t and ptrdiff_t.
+ * From 1.6.0 onwards, an ISO C90 compiler, as well as a standard-compliant
+ * behavior of sizeof and ptrdiff_t are required.
+ * The legacy typedefs are provided here for backwards compatibility.
  */
 typedef size_t png_size_t;
 typedef ptrdiff_t png_ptrdiff_t;
@@ -537,13 +539,12 @@
 #  endif
 #endif
 
-/* png_alloc_size_t is guaranteed to be no smaller than png_size_t, and no
- * smaller than png_uint_32.  Casts from png_size_t or png_uint_32 to
- * png_alloc_size_t are not necessary; in fact, it is recommended not to use
- * them at all so that the compiler can complain when something turns out to be
- * problematic.
+/* png_alloc_size_t is guaranteed to be no smaller than size_t, and no smaller
+ * than png_uint_32.  Casts from size_t or png_uint_32 to png_alloc_size_t are
+ * not necessary; in fact, it is recommended not to use them at all, so that
+ * the compiler can complain when something turns out to be problematic.
  *
- * Casts in the other direction (from png_alloc_size_t to png_size_t or
+ * Casts in the other direction (from png_alloc_size_t to size_t or
  * png_uint_32) should be explicitly applied; however, we do not expect to
  * encounter practical situations that require such conversions.
  *
@@ -553,7 +554,7 @@
 #ifdef PNG_SMALL_SIZE_T
    typedef png_uint_32 png_alloc_size_t;
 #else
-   typedef png_size_t png_alloc_size_t;
+   typedef size_t png_alloc_size_t;
 #endif
 
 /* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler
@@ -589,8 +590,8 @@
 typedef const char            * png_const_charp;
 typedef png_fixed_point       * png_fixed_point_p;
 typedef const png_fixed_point * png_const_fixed_point_p;
-typedef png_size_t            * png_size_tp;
-typedef const png_size_t      * png_const_size_tp;
+typedef size_t                * png_size_tp;
+typedef const size_t          * png_const_size_tp;
 
 #ifdef PNG_STDIO_SUPPORTED
 typedef FILE            * png_FILE_p;
diff --git a/pngget.c b/pngget.c
index b888db3..9e85726 100644
--- a/pngget.c
+++ b/pngget.c
@@ -26,7 +26,7 @@
    return(0);
 }
 
-png_size_t PNGAPI
+size_t PNGAPI
 png_get_rowbytes(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
@@ -1165,7 +1165,7 @@
 }
 #endif
 
-png_size_t PNGAPI
+size_t PNGAPI
 png_get_compression_buffer_size(png_const_structrp png_ptr)
 {
    if (png_ptr == NULL)
diff --git a/pnginfo.h b/pnginfo.h
index 3ef3819..2b5e6e8 100644
--- a/pnginfo.h
+++ b/pnginfo.h
@@ -55,10 +55,10 @@
 struct png_info_def
 {
    /* The following are necessary for every PNG file */
-   png_uint_32 width;  /* width of image in pixels (from IHDR) */
-   png_uint_32 height; /* height of image in pixels (from IHDR) */
-   png_uint_32 valid;  /* valid chunk data (see PNG_INFO_ below) */
-   png_size_t rowbytes; /* bytes needed to hold an untransformed row */
+   png_uint_32 width;       /* width of image in pixels (from IHDR) */
+   png_uint_32 height;      /* height of image in pixels (from IHDR) */
+   png_uint_32 valid;       /* valid chunk data (see PNG_INFO_ below) */
+   size_t rowbytes;         /* bytes needed to hold an untransformed row */
    png_colorp palette;      /* array of color values (valid & PNG_INFO_PLTE) */
    png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
    png_uint_16 num_trans;   /* number of transparent palette color (tRNS) */
diff --git a/pngpread.c b/pngpread.c
index fbe361d..50d8d70 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -34,7 +34,7 @@
 
 void PNGAPI
 png_process_data(png_structrp png_ptr, png_inforp info_ptr,
-    png_bytep buffer, png_size_t buffer_size)
+    png_bytep buffer, size_t buffer_size)
 {
    if (png_ptr == NULL || info_ptr == NULL)
       return;
@@ -47,7 +47,7 @@
    }
 }
 
-png_size_t PNGAPI
+size_t PNGAPI
 png_process_data_pause(png_structrp png_ptr, int save)
 {
    if (png_ptr != NULL)
@@ -60,7 +60,7 @@
       else
       {
          /* This includes any pending saved bytes: */
-         png_size_t remaining = png_ptr->buffer_size;
+         size_t remaining = png_ptr->buffer_size;
          png_ptr->buffer_size = 0;
 
          /* So subtract the saved buffer size, unless all the data
@@ -133,8 +133,8 @@
 void /* PRIVATE */
 png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
 {
-   png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */
-       num_to_check = 8 - num_checked;
+   size_t num_checked = png_ptr->sig_bytes; /* SAFE, does not exceed 8 */
+   size_t num_to_check = 8 - num_checked;
 
    if (png_ptr->buffer_size < num_to_check)
    {
@@ -418,7 +418,7 @@
 }
 
 void PNGCBAPI
-png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
+png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, size_t length)
 {
    png_bytep ptr;
 
@@ -428,7 +428,7 @@
    ptr = buffer;
    if (png_ptr->save_buffer_size != 0)
    {
-      png_size_t save_size;
+      size_t save_size;
 
       if (length < png_ptr->save_buffer_size)
          save_size = length;
@@ -445,7 +445,7 @@
    }
    if (length != 0 && png_ptr->current_buffer_size != 0)
    {
-      png_size_t save_size;
+      size_t save_size;
 
       if (length < png_ptr->current_buffer_size)
          save_size = length;
@@ -467,7 +467,7 @@
    {
       if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
       {
-         png_size_t i, istop;
+         size_t i, istop;
          png_bytep sp;
          png_bytep dp;
 
@@ -482,7 +482,7 @@
    if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
        png_ptr->save_buffer_max)
    {
-      png_size_t new_max;
+      size_t new_max;
       png_bytep old_buffer;
 
       if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
@@ -494,7 +494,7 @@
       new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
       old_buffer = png_ptr->save_buffer;
       png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
-          (png_size_t)new_max);
+          (size_t)new_max);
 
       if (png_ptr->save_buffer == NULL)
       {
@@ -522,7 +522,7 @@
 
 void /* PRIVATE */
 png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
-    png_size_t buffer_length)
+    size_t buffer_length)
 {
    png_ptr->current_buffer = buffer;
    png_ptr->current_buffer_size = buffer_length;
@@ -562,7 +562,7 @@
 
    if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
    {
-      png_size_t save_size = png_ptr->save_buffer_size;
+      size_t save_size = png_ptr->save_buffer_size;
       png_uint_32 idat_size = png_ptr->idat_size;
 
       /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
@@ -572,7 +572,7 @@
        * will break on either 16-bit or 64-bit platforms.
        */
       if (idat_size < save_size)
-         save_size = (png_size_t)idat_size;
+         save_size = (size_t)idat_size;
 
       else
          idat_size = (png_uint_32)save_size;
@@ -589,7 +589,7 @@
 
    if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
    {
-      png_size_t save_size = png_ptr->current_buffer_size;
+      size_t save_size = png_ptr->current_buffer_size;
       png_uint_32 idat_size = png_ptr->idat_size;
 
       /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
@@ -598,7 +598,7 @@
        * larger - this cannot overflow.
        */
       if (idat_size < save_size)
-         save_size = (png_size_t)idat_size;
+         save_size = (size_t)idat_size;
 
       else
          idat_size = (png_uint_32)save_size;
@@ -625,7 +625,7 @@
 
 void /* PRIVATE */
 png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
-    png_size_t buffer_length)
+    size_t buffer_length)
 {
    /* The caller checks for a non-zero buffer length. */
    if (!(buffer_length > 0) || buffer == NULL)
diff --git a/pngpriv.h b/pngpriv.h
index a7851cd..ec5285f 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -734,8 +734,8 @@
 /* Added to libpng-1.2.6 JB */
 #define PNG_ROWBYTES(pixel_bits, width) \
     ((pixel_bits) >= 8 ? \
-    ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
-    (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
+    ((size_t)(width) * (((size_t)(pixel_bits)) >> 3)) : \
+    (( ((size_t)(width) * ((size_t)(pixel_bits))) + 7) >> 3) )
 
 /* This returns the number of trailing bits in the last byte of a row, 0 if the
  * last byte is completely full of pixels.  It is, in principle, (pixel_bits x
@@ -1052,15 +1052,15 @@
  */
 
 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
-    png_bytep data, png_size_t length),PNG_EMPTY);
+    png_bytep data, size_t length),PNG_EMPTY);
 
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
-    png_bytep buffer, png_size_t length),PNG_EMPTY);
+    png_bytep buffer, size_t length),PNG_EMPTY);
 #endif
 
 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
-    png_bytep data, png_size_t length),PNG_EMPTY);
+    png_bytep data, size_t length),PNG_EMPTY);
 
 #ifdef PNG_WRITE_FLUSH_SUPPORTED
 #  ifdef PNG_STDIO_SUPPORTED
@@ -1074,7 +1074,7 @@
 
 /* Write the "data" buffer to whatever output you are using */
 PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
-    png_const_bytep data, png_size_t length),PNG_EMPTY);
+    png_const_bytep data, size_t length),PNG_EMPTY);
 
 /* Read and check the PNG file signature */
 PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
@@ -1086,7 +1086,7 @@
 
 /* Read data from whatever input you are using into the "data" buffer */
 PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
-    png_size_t length),PNG_EMPTY);
+    size_t length),PNG_EMPTY);
 
 /* Read bytes into buf, and update png_ptr->crc */
 PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
@@ -1104,7 +1104,7 @@
  * since this is the maximum buffer size we can specify.
  */
 PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
-   png_const_bytep ptr, png_size_t length),PNG_EMPTY);
+   png_const_bytep ptr, size_t length),PNG_EMPTY);
 
 #ifdef PNG_WRITE_FLUSH_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
@@ -1187,7 +1187,7 @@
 /* Chunks that have keywords */
 #ifdef PNG_WRITE_tEXt_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
-   png_const_charp key, png_const_charp text, png_size_t text_len),PNG_EMPTY);
+   png_const_charp key, png_const_charp text, size_t text_len),PNG_EMPTY);
 #endif
 
 #ifdef PNG_WRITE_zTXt_SUPPORTED
@@ -1580,10 +1580,10 @@
 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
     PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
-    png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
+    png_bytep buffer, size_t buffer_length),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
-    png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
+    png_bytep buffer, size_t buffer_length),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
     PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
@@ -1853,13 +1853,13 @@
 
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
-   png_charp ascii, png_size_t size, double fp, unsigned int precision),
+   png_charp ascii, size_t size, double fp, unsigned int precision),
    PNG_EMPTY);
 #endif /* FLOATING_POINT */
 
 #ifdef PNG_FIXED_POINT_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
-   png_charp ascii, png_size_t size, png_fixed_point fp),PNG_EMPTY);
+   png_charp ascii, size_t size, png_fixed_point fp),PNG_EMPTY);
 #endif /* FIXED_POINT */
 #endif /* sCAL */
 
@@ -1952,7 +1952,7 @@
  * the problem character.)  This has not been tested within libpng.
  */
 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
-   png_size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
+   size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
 
 /* This is the same but it checks a complete string and returns true
  * only if it just contains a floating point number.  As of 1.5.4 this
@@ -1961,7 +1961,7 @@
  * for negative or zero values using the sticky flag.
  */
 PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
-   png_size_t size),PNG_EMPTY);
+   size_t size),PNG_EMPTY);
 #endif /* pCAL || sCAL */
 
 #if defined(PNG_GAMMA_SUPPORTED) ||\
@@ -2036,7 +2036,7 @@
    png_voidp   error_buf;           /* Always a jmp_buf at present. */
 
    png_const_bytep memory;          /* Memory buffer. */
-   png_size_t      size;            /* Size of the memory buffer. */
+   size_t          size;            /* Size of the memory buffer. */
 
    unsigned int for_write       :1; /* Otherwise it is a read structure */
    unsigned int owned_file      :1; /* We own the file in io_ptr */
diff --git a/pngread.c b/pngread.c
index 5dcb298..208b9a3 100644
--- a/pngread.c
+++ b/pngread.c
@@ -1532,7 +1532,7 @@
 #endif /* STDIO */
 
 static void PNGCBAPI
-png_image_memory_read(png_structp png_ptr, png_bytep out, png_size_t need)
+png_image_memory_read(png_structp png_ptr, png_bytep out, size_t need)
 {
    if (png_ptr != NULL)
    {
@@ -1543,7 +1543,7 @@
          if (cp != NULL)
          {
             png_const_bytep memory = cp->memory;
-            png_size_t size = cp->size;
+            size_t size = cp->size;
 
             if (memory != NULL && size >= need)
             {
@@ -1562,7 +1562,7 @@
 }
 
 int PNGAPI png_image_begin_read_from_memory(png_imagep image,
-    png_const_voidp memory, png_size_t size)
+    png_const_voidp memory, size_t size)
 {
    if (image != NULL && image->version == PNG_IMAGE_VERSION)
    {
diff --git a/pngrio.c b/pngrio.c
index 7e26e85..f889d4a 100644
--- a/pngrio.c
+++ b/pngrio.c
@@ -29,7 +29,7 @@
  * to read more than 64K on a 16-bit machine.
  */
 void /* PRIVATE */
-png_read_data(png_structrp png_ptr, png_bytep data, png_size_t length)
+png_read_data(png_structrp png_ptr, png_bytep data, size_t length)
 {
    png_debug1(4, "reading %d bytes", (int)length);
 
@@ -47,14 +47,14 @@
  * than changing the library.
  */
 void PNGCBAPI
-png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
+png_default_read_data(png_structp png_ptr, png_bytep data, size_t length)
 {
-   png_size_t check;
+   size_t check;
 
    if (png_ptr == NULL)
       return;
 
-   /* fread() returns 0 on error, so it is OK to store this in a png_size_t
+   /* fread() returns 0 on error, so it is OK to store this in a size_t
     * instead of an int, which is what fread() actually returns.
     */
    check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr));
diff --git a/pngrtran.c b/pngrtran.c
index 8cfb331..2ba4dca 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -747,7 +747,7 @@
       int num_red = (1 << PNG_QUANTIZE_RED_BITS);
       int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
       int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);
-      png_size_t num_entries = ((png_size_t)1 << total_bits);
+      size_t num_entries = ((size_t)1 << total_bits);
 
       png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr,
           (png_alloc_size_t)(num_entries * (sizeof (png_byte))));
@@ -2151,8 +2151,8 @@
       {
          case 1:
          {
-            png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
-            png_bytep dp = row + (png_size_t)row_width - 1;
+            png_bytep sp = row + (size_t)((row_width - 1) >> 3);
+            png_bytep dp = row + (size_t)row_width - 1;
             png_uint_32 shift = 7U - ((row_width + 7U) & 0x07);
             for (i = 0; i < row_width; i++)
             {
@@ -2175,8 +2175,8 @@
          case 2:
          {
 
-            png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
-            png_bytep dp = row + (png_size_t)row_width - 1;
+            png_bytep sp = row + (size_t)((row_width - 1) >> 2);
+            png_bytep dp = row + (size_t)row_width - 1;
             png_uint_32 shift = ((3U - ((row_width + 3U) & 0x03)) << 1);
             for (i = 0; i < row_width; i++)
             {
@@ -2198,8 +2198,8 @@
 
          case 4:
          {
-            png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
-            png_bytep dp = row + (png_size_t)row_width - 1;
+            png_bytep sp = row + (size_t)((row_width - 1) >> 1);
+            png_bytep dp = row + (size_t)row_width - 1;
             png_uint_32 shift = ((1U - ((row_width + 1U) & 0x01)) << 2);
             for (i = 0; i < row_width; i++)
             {
@@ -2680,8 +2680,8 @@
          if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
          {
             /* This changes the data from G to GX */
-            png_bytep sp = row + (png_size_t)row_width;
-            png_bytep dp =  sp + (png_size_t)row_width;
+            png_bytep sp = row + (size_t)row_width;
+            png_bytep dp =  sp + (size_t)row_width;
             for (i = 1; i < row_width; i++)
             {
                *(--dp) = lo_filler;
@@ -2696,8 +2696,8 @@
          else
          {
             /* This changes the data from G to XG */
-            png_bytep sp = row + (png_size_t)row_width;
-            png_bytep dp = sp  + (png_size_t)row_width;
+            png_bytep sp = row + (size_t)row_width;
+            png_bytep dp = sp  + (size_t)row_width;
             for (i = 0; i < row_width; i++)
             {
                *(--dp) = *(--sp);
@@ -2715,8 +2715,8 @@
          if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
          {
             /* This changes the data from GG to GGXX */
-            png_bytep sp = row + (png_size_t)row_width * 2;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            png_bytep sp = row + (size_t)row_width * 2;
+            png_bytep dp = sp  + (size_t)row_width * 2;
             for (i = 1; i < row_width; i++)
             {
                *(--dp) = lo_filler;
@@ -2734,8 +2734,8 @@
          else
          {
             /* This changes the data from GG to XXGG */
-            png_bytep sp = row + (png_size_t)row_width * 2;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            png_bytep sp = row + (size_t)row_width * 2;
+            png_bytep dp = sp  + (size_t)row_width * 2;
             for (i = 0; i < row_width; i++)
             {
                *(--dp) = *(--sp);
@@ -2757,8 +2757,8 @@
          if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
          {
             /* This changes the data from RGB to RGBX */
-            png_bytep sp = row + (png_size_t)row_width * 3;
-            png_bytep dp = sp  + (png_size_t)row_width;
+            png_bytep sp = row + (size_t)row_width * 3;
+            png_bytep dp = sp  + (size_t)row_width;
             for (i = 1; i < row_width; i++)
             {
                *(--dp) = lo_filler;
@@ -2775,8 +2775,8 @@
          else
          {
             /* This changes the data from RGB to XRGB */
-            png_bytep sp = row + (png_size_t)row_width * 3;
-            png_bytep dp = sp + (png_size_t)row_width;
+            png_bytep sp = row + (size_t)row_width * 3;
+            png_bytep dp = sp + (size_t)row_width;
             for (i = 0; i < row_width; i++)
             {
                *(--dp) = *(--sp);
@@ -2796,8 +2796,8 @@
          if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
          {
             /* This changes the data from RRGGBB to RRGGBBXX */
-            png_bytep sp = row + (png_size_t)row_width * 6;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            png_bytep sp = row + (size_t)row_width * 6;
+            png_bytep dp = sp  + (size_t)row_width * 2;
             for (i = 1; i < row_width; i++)
             {
                *(--dp) = lo_filler;
@@ -2819,8 +2819,8 @@
          else
          {
             /* This changes the data from RRGGBB to XXRRGGBB */
-            png_bytep sp = row + (png_size_t)row_width * 6;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            png_bytep sp = row + (size_t)row_width * 6;
+            png_bytep dp = sp  + (size_t)row_width * 2;
             for (i = 0; i < row_width; i++)
             {
                *(--dp) = *(--sp);
@@ -2861,8 +2861,8 @@
          if (row_info->bit_depth == 8)
          {
             /* This changes G to RGB */
-            png_bytep sp = row + (png_size_t)row_width - 1;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            png_bytep sp = row + (size_t)row_width - 1;
+            png_bytep dp = sp  + (size_t)row_width * 2;
             for (i = 0; i < row_width; i++)
             {
                *(dp--) = *sp;
@@ -2874,8 +2874,8 @@
          else
          {
             /* This changes GG to RRGGBB */
-            png_bytep sp = row + (png_size_t)row_width * 2 - 1;
-            png_bytep dp = sp  + (png_size_t)row_width * 4;
+            png_bytep sp = row + (size_t)row_width * 2 - 1;
+            png_bytep dp = sp  + (size_t)row_width * 4;
             for (i = 0; i < row_width; i++)
             {
                *(dp--) = *sp;
@@ -2893,8 +2893,8 @@
          if (row_info->bit_depth == 8)
          {
             /* This changes GA to RGBA */
-            png_bytep sp = row + (png_size_t)row_width * 2 - 1;
-            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            png_bytep sp = row + (size_t)row_width * 2 - 1;
+            png_bytep dp = sp  + (size_t)row_width * 2;
             for (i = 0; i < row_width; i++)
             {
                *(dp--) = *(sp--);
@@ -2907,8 +2907,8 @@
          else
          {
             /* This changes GGAA to RRGGBBAA */
-            png_bytep sp = row + (png_size_t)row_width * 4 - 1;
-            png_bytep dp = sp  + (png_size_t)row_width * 4;
+            png_bytep sp = row + (size_t)row_width * 4 - 1;
+            png_bytep dp = sp  + (size_t)row_width * 4;
             for (i = 0; i < row_width; i++)
             {
                *(dp--) = *(sp--);
@@ -4217,8 +4217,8 @@
          {
             case 1:
             {
-               sp = row + (png_size_t)((row_width - 1) >> 3);
-               dp = row + (png_size_t)row_width - 1;
+               sp = row + (size_t)((row_width - 1) >> 3);
+               dp = row + (size_t)row_width - 1;
                shift = 7 - (int)((row_width + 7) & 0x07);
                for (i = 0; i < row_width; i++)
                {
@@ -4244,8 +4244,8 @@
 
             case 2:
             {
-               sp = row + (png_size_t)((row_width - 1) >> 2);
-               dp = row + (png_size_t)row_width - 1;
+               sp = row + (size_t)((row_width - 1) >> 2);
+               dp = row + (size_t)row_width - 1;
                shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
                for (i = 0; i < row_width; i++)
                {
@@ -4267,8 +4267,8 @@
 
             case 4:
             {
-               sp = row + (png_size_t)((row_width - 1) >> 1);
-               dp = row + (png_size_t)row_width - 1;
+               sp = row + (size_t)((row_width - 1) >> 1);
+               dp = row + (size_t)row_width - 1;
                shift = (int)((row_width & 0x01) << 2);
                for (i = 0; i < row_width; i++)
                {
@@ -4301,8 +4301,8 @@
          {
             if (num_trans > 0)
             {
-               sp = row + (png_size_t)row_width - 1;
-               dp = row + ((png_size_t)row_width << 2) - 1;
+               sp = row + (size_t)row_width - 1;
+               dp = row + ((size_t)row_width << 2) - 1;
 
                for (i = 0; i < row_width; i++)
                {
@@ -4326,8 +4326,8 @@
 
             else
             {
-               sp = row + (png_size_t)row_width - 1;
-               dp = row + (png_size_t)(row_width * 3) - 1;
+               sp = row + (size_t)row_width - 1;
+               dp = row + (size_t)(row_width * 3) - 1;
 
                for (i = 0; i < row_width; i++)
                {
@@ -4373,8 +4373,8 @@
             case 1:
             {
                gray = (gray & 0x01) * 0xff;
-               sp = row + (png_size_t)((row_width - 1) >> 3);
-               dp = row + (png_size_t)row_width - 1;
+               sp = row + (size_t)((row_width - 1) >> 3);
+               dp = row + (size_t)row_width - 1;
                shift = 7 - (int)((row_width + 7) & 0x07);
                for (i = 0; i < row_width; i++)
                {
@@ -4401,8 +4401,8 @@
             case 2:
             {
                gray = (gray & 0x03) * 0x55;
-               sp = row + (png_size_t)((row_width - 1) >> 2);
-               dp = row + (png_size_t)row_width - 1;
+               sp = row + (size_t)((row_width - 1) >> 2);
+               dp = row + (size_t)row_width - 1;
                shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
                for (i = 0; i < row_width; i++)
                {
@@ -4426,8 +4426,8 @@
             case 4:
             {
                gray = (gray & 0x0f) * 0x11;
-               sp = row + (png_size_t)((row_width - 1) >> 1);
-               dp = row + (png_size_t)row_width - 1;
+               sp = row + (size_t)((row_width - 1) >> 1);
+               dp = row + (size_t)row_width - 1;
                shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
                for (i = 0; i < row_width; i++)
                {
@@ -4461,8 +4461,8 @@
          if (row_info->bit_depth == 8)
          {
             gray = gray & 0xff;
-            sp = row + (png_size_t)row_width - 1;
-            dp = row + ((png_size_t)row_width << 1) - 1;
+            sp = row + (size_t)row_width - 1;
+            dp = row + ((size_t)row_width << 1) - 1;
 
             for (i = 0; i < row_width; i++)
             {
@@ -4517,8 +4517,8 @@
          png_byte red = (png_byte)(trans_color->red & 0xff);
          png_byte green = (png_byte)(trans_color->green & 0xff);
          png_byte blue = (png_byte)(trans_color->blue & 0xff);
-         sp = row + (png_size_t)row_info->rowbytes - 1;
-         dp = row + ((png_size_t)row_width << 2) - 1;
+         sp = row + (size_t)row_info->rowbytes - 1;
+         dp = row + ((size_t)row_width << 2) - 1;
          for (i = 0; i < row_width; i++)
          {
             if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
@@ -4541,7 +4541,7 @@
          png_byte green_low = (png_byte)(trans_color->green & 0xff);
          png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
          sp = row + row_info->rowbytes - 1;
-         dp = row + ((png_size_t)row_width << 3) - 1;
+         dp = row + ((size_t)row_width << 3) - 1;
          for (i = 0; i < row_width; i++)
          {
             if (*(sp - 5) == red_high &&
@@ -4979,7 +4979,7 @@
              (png_ptr,     /* png_ptr */
              row_info,     /* row_info: */
                 /*  png_uint_32 width;       width of row */
-                /*  png_size_t rowbytes;     number of bytes in row */
+                /*  size_t rowbytes;         number of bytes in row */
                 /*  png_byte color_type;     color type of pixels */
                 /*  png_byte bit_depth;      bit depth of samples */
                 /*  png_byte channels;       number of channels (1-4) */
diff --git a/pngrutil.c b/pngrutil.c
index fafe78f..95571b5 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -120,7 +120,7 @@
 void /* PRIVATE */
 png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
 {
-   png_size_t num_checked, num_to_check;
+   size_t num_checked, num_to_check;
 
    /* Exit if the user application does not expect a signature. */
    if (png_ptr->sig_bytes >= 8)
@@ -1648,7 +1648,7 @@
    int entry_size, i;
    png_uint_32 skip = 0;
    png_uint_32 dl;
-   png_size_t max_dl;
+   size_t max_dl;
 
    png_debug(1, "in png_handle_sPLT");
 
@@ -2377,7 +2377,7 @@
 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
 {
    png_bytep buffer;
-   png_size_t i;
+   size_t i;
    int state;
 
    png_debug(1, "in png_handle_sCAL");
@@ -2447,7 +2447,7 @@
 
    else
    {
-      png_size_t heighti = i;
+      size_t heighti = i;
 
       state = 0;
       if (png_check_fp_number((png_const_charp)buffer, length,
@@ -2885,7 +2885,7 @@
    {
       PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
       /* The following is safe because of the PNG_SIZE_MAX init above */
-      png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
+      png_ptr->unknown_chunk.size = (size_t)length/*SAFE*/;
       /* 'mode' is a flag array, only the bottom four bits matter here */
       png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
 
@@ -3697,8 +3697,8 @@
       {
          case 1:
          {
-            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
-            png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
+            png_bytep sp = row + (size_t)((row_info->width - 1) >> 3);
+            png_bytep dp = row + (size_t)((final_width - 1) >> 3);
             unsigned int sshift, dshift;
             unsigned int s_start, s_end;
             int s_inc;
@@ -3824,8 +3824,8 @@
 
          case 4:
          {
-            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
-            png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
+            png_bytep sp = row + (size_t)((row_info->width - 1) >> 1);
+            png_bytep dp = row + (size_t)((final_width - 1) >> 1);
             unsigned int sshift, dshift;
             unsigned int s_start, s_end;
             int s_inc;
@@ -3887,12 +3887,12 @@
 
          default:
          {
-            png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
+            size_t pixel_bytes = (row_info->pixel_depth >> 3);
 
-            png_bytep sp = row + (png_size_t)(row_info->width - 1)
+            png_bytep sp = row + (size_t)(row_info->width - 1)
                 * pixel_bytes;
 
-            png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
+            png_bytep dp = row + (size_t)(final_width - 1) * pixel_bytes;
 
             int jstop = (int)png_pass_inc[pass];
             png_uint_32 i;
@@ -3929,8 +3929,8 @@
 png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
     png_const_bytep prev_row)
 {
-   png_size_t i;
-   png_size_t istop = row_info->rowbytes;
+   size_t i;
+   size_t istop = row_info->rowbytes;
    unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
    png_bytep rp = row + bpp;
 
@@ -3947,8 +3947,8 @@
 png_read_filter_row_up(png_row_infop row_info, png_bytep row,
     png_const_bytep prev_row)
 {
-   png_size_t i;
-   png_size_t istop = row_info->rowbytes;
+   size_t i;
+   size_t istop = row_info->rowbytes;
    png_bytep rp = row;
    png_const_bytep pp = prev_row;
 
@@ -3963,11 +3963,11 @@
 png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
     png_const_bytep prev_row)
 {
-   png_size_t i;
+   size_t i;
    png_bytep rp = row;
    png_const_bytep pp = prev_row;
    unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
-   png_size_t istop = row_info->rowbytes - bpp;
+   size_t istop = row_info->rowbytes - bpp;
 
    for (i = 0; i < bpp; i++)
    {
@@ -4403,7 +4403,7 @@
    static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 
    unsigned int max_pixel_depth;
-   png_size_t row_bytes;
+   size_t row_bytes;
 
    png_debug(1, "in png_read_start_row");
 
diff --git a/pngset.c b/pngset.c
index 6f3a1ee..c96af50 100644
--- a/pngset.c
+++ b/pngset.c
@@ -313,7 +313,7 @@
     png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type,
     int nparams, png_const_charp units, png_charpp params)
 {
-   png_size_t length;
+   size_t length;
    int i;
 
    png_debug1(1, "in %s storage function", "pCAL");
@@ -390,7 +390,7 @@
    memcpy(info_ptr->pcal_units, units, length);
 
    info_ptr->pcal_params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
-       (png_size_t)(((unsigned int)nparams + 1) * (sizeof (png_charp)))));
+       (size_t)(((unsigned int)nparams + 1) * (sizeof (png_charp)))));
 
    if (info_ptr->pcal_params == NULL)
    {
@@ -430,7 +430,7 @@
 png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
     int unit, png_const_charp swidth, png_const_charp sheight)
 {
-   png_size_t lengthw = 0, lengthh = 0;
+   size_t lengthw = 0, lengthh = 0;
 
    png_debug1(1, "in %s storage function", "sCAL");
 
@@ -691,7 +691,7 @@
 {
    png_charp new_iccp_name;
    png_bytep new_iccp_profile;
-   png_size_t length;
+   size_t length;
 
    png_debug1(1, "in %s storage function", "iCCP");
 
@@ -1018,7 +1018,7 @@
          /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
           info_ptr->trans_alpha = png_voidcast(png_bytep,
               png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));
-          memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans);
+          memcpy(info_ptr->trans_alpha, trans_alpha, (size_t)num_trans);
        }
        png_ptr->trans_alpha = info_ptr->trans_alpha;
    }
@@ -1098,7 +1098,7 @@
 
    do
    {
-      png_size_t length;
+      size_t length;
 
       /* Skip invalid input entries */
       if (entries->name == NULL || entries->entries == NULL)
@@ -1563,7 +1563,7 @@
 #endif
 
 void PNGAPI
-png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
+png_set_compression_buffer_size(png_structrp png_ptr, size_t size)
 {
    if (png_ptr == NULL)
       return;
diff --git a/pngstruct.h b/pngstruct.h
index b5cabe9..26ea2d5 100644
--- a/pngstruct.h
+++ b/pngstruct.h
@@ -47,7 +47,7 @@
 /* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
  * can handle at once.  This type need be no larger than 16 bits (so maximum of
  * 65535), this define allows us to discover how big it is, but limited by the
- * maximuum for png_size_t.  The value can be overridden in a library build
+ * maximum for size_t.  The value can be overridden in a library build
  * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
  * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
  * and may even improve performance on some systems (and degrade it on others.)
@@ -214,7 +214,7 @@
    png_uint_32 height;        /* height of image in pixels */
    png_uint_32 num_rows;      /* number of rows in current pass */
    png_uint_32 usr_width;     /* width of row at start of write */
-   png_size_t rowbytes;       /* size of row in bytes */
+   size_t rowbytes;           /* size of row in bytes */
    png_uint_32 iwidth;        /* width of current interlaced row in pixels */
    png_uint_32 row_number;    /* current row in interlace pass */
    png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
@@ -232,7 +232,7 @@
    png_bytep try_row;    /* buffer to save trial row when filtering */
    png_bytep tst_row;    /* buffer to save best trial row when filtering */
 #endif
-   png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
+   size_t info_rowbytes;      /* Added in 1.5.4: cache of updated row bytes */
 
    png_uint_32 idat_size;     /* current IDAT size for read */
    png_uint_32 crc;           /* current chunk CRC value */
@@ -328,10 +328,10 @@
    png_bytep current_buffer;         /* buffer for recently used data */
    png_uint_32 push_length;          /* size of current input chunk */
    png_uint_32 skip_length;          /* bytes to skip in input data */
-   png_size_t save_buffer_size;      /* amount of data now in save_buffer */
-   png_size_t save_buffer_max;       /* total size of save_buffer */
-   png_size_t buffer_size;           /* total amount of available input data */
-   png_size_t current_buffer_size;   /* amount of data now in current_buffer */
+   size_t save_buffer_size;          /* amount of data now in save_buffer */
+   size_t save_buffer_max;           /* total size of save_buffer */
+   size_t buffer_size;               /* total amount of available input data */
+   size_t current_buffer_size;       /* amount of data now in current_buffer */
    int process_mode;                 /* what push library is currently doing */
    int cur_palette;                  /* current push library palette index */
 
@@ -451,7 +451,7 @@
 #endif
 
 /* New member added in libpng-1.2.26 */
-  png_size_t old_big_row_buf_size;
+   size_t old_big_row_buf_size;
 
 #ifdef PNG_READ_SUPPORTED
 /* New member added in libpng-1.2.30 */
diff --git a/pngtest.c b/pngtest.c
index 61a2064..a6d6f14 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -345,10 +345,10 @@
 
 #ifdef PNG_IO_STATE_SUPPORTED
 void
-pngtest_check_io_state(png_structp png_ptr, png_size_t data_length,
+pngtest_check_io_state(png_structp png_ptr, size_t data_length,
     png_uint_32 io_op);
 void
-pngtest_check_io_state(png_structp png_ptr, png_size_t data_length,
+pngtest_check_io_state(png_structp png_ptr, size_t data_length,
     png_uint_32 io_op)
 {
    png_uint_32 io_state = png_get_io_state(png_ptr);
@@ -386,12 +386,12 @@
 #endif
 
 static void PNGCBAPI
-pngtest_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
+pngtest_read_data(png_structp png_ptr, png_bytep data, size_t length)
 {
-   png_size_t check = 0;
+   size_t check = 0;
    png_voidp io_ptr;
 
-   /* fread() returns 0 on error, so it is OK to store this in a png_size_t
+   /* fread() returns 0 on error, so it is OK to store this in a size_t
     * instead of an int, which is what fread() actually returns.
     */
    io_ptr = png_get_io_ptr(png_ptr);
@@ -425,9 +425,9 @@
  * than changing the library.
  */
 static void PNGCBAPI
-pngtest_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+pngtest_write_data(png_structp png_ptr, png_bytep data, size_t length)
 {
-   png_size_t check;
+   size_t check;
 
    check = fwrite(data, 1, length, (png_FILE_p)png_get_io_ptr(png_ptr));
 
@@ -705,7 +705,7 @@
     * The unknown chunk structure contains the chunk data:
     * png_byte name[5];
     * png_byte *data;
-    * png_size_t size;
+    * size_t size;
     *
     * Note that libpng has already taken care of the CRC handling.
     */
@@ -1726,7 +1726,7 @@
       for (;;)
       {
          static int wrote_question = 0;
-         png_size_t num_in, num_out;
+         size_t num_in, num_out;
          char inbuf[256], outbuf[256];
 
          num_in = fread(inbuf, 1, sizeof inbuf, fpin);
diff --git a/pngtrans.c b/pngtrans.c
index 6882f0f..19a6160 100644
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -269,8 +269,8 @@
    if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
    {
       png_bytep rp = row;
-      png_size_t i;
-      png_size_t istop = row_info->rowbytes;
+      size_t i;
+      size_t istop = row_info->rowbytes;
 
       for (i = 0; i < istop; i++)
       {
@@ -283,8 +283,8 @@
       row_info->bit_depth == 8)
    {
       png_bytep rp = row;
-      png_size_t i;
-      png_size_t istop = row_info->rowbytes;
+      size_t i;
+      size_t istop = row_info->rowbytes;
 
       for (i = 0; i < istop; i += 2)
       {
@@ -298,8 +298,8 @@
       row_info->bit_depth == 16)
    {
       png_bytep rp = row;
-      png_size_t i;
-      png_size_t istop = row_info->rowbytes;
+      size_t i;
+      size_t istop = row_info->rowbytes;
 
       for (i = 0; i < istop; i += 4)
       {
@@ -609,7 +609,7 @@
       return; /* The filler channel has gone already */
 
    /* Fix the rowbytes value. */
-   row_info->rowbytes = (png_size_t)(dp-row);
+   row_info->rowbytes = (size_t)(dp-row);
 }
 #endif
 
diff --git a/pngwio.c b/pngwio.c
index 37c7c3a..3a76173 100644
--- a/pngwio.c
+++ b/pngwio.c
@@ -30,7 +30,7 @@
  */
 
 void /* PRIVATE */
-png_write_data(png_structrp png_ptr, png_const_bytep data, png_size_t length)
+png_write_data(png_structrp png_ptr, png_const_bytep data, size_t length)
 {
    /* NOTE: write_data_fn must not change the buffer! */
    if (png_ptr->write_data_fn != NULL )
@@ -48,9 +48,9 @@
  * than changing the library.
  */
 void PNGCBAPI
-png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+png_default_write_data(png_structp png_ptr, png_bytep data, size_t length)
 {
-   png_size_t check;
+   size_t check;
 
    if (png_ptr == NULL)
       return;
diff --git a/pngwrite.c b/pngwrite.c
index a16d77c..e526cba 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -2162,8 +2162,7 @@
 
 
 static void (PNGCBAPI
-image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data,
-    png_size_t size)
+image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data, size_t size)
 {
    png_image_write_control *display = png_voidcast(png_image_write_control*,
        png_ptr->io_ptr/*backdoor: png_get_io_ptr(png_ptr)*/);
diff --git a/pngwtran.c b/pngwtran.c
index 377b43e..71963fd 100644
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -212,9 +212,9 @@
       if (row_info->bit_depth < 8)
       {
          png_bytep bp = row;
-         png_size_t i;
+         size_t i;
          unsigned int mask;
-         png_size_t row_bytes = row_info->rowbytes;
+         size_t row_bytes = row_info->rowbytes;
 
          if (bit_depth->gray == 1 && row_info->bit_depth == 2)
             mask = 0x55;
@@ -514,7 +514,7 @@
              (png_ptr,  /* png_ptr */
              row_info,  /* row_info: */
                 /*  png_uint_32 width;       width of row */
-                /*  png_size_t rowbytes;     number of bytes in row */
+                /*  size_t rowbytes;         number of bytes in row */
                 /*  png_byte color_type;     color type of pixels */
                 /*  png_byte bit_depth;      bit depth of samples */
                 /*  png_byte channels;       number of channels (1-4) */
diff --git a/pngwutil.c b/pngwutil.c
index 0d4fb13..12bb945 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -59,7 +59,7 @@
 
    /* Write the rest of the 8 byte signature */
    png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
-       (png_size_t)(8 - png_ptr->sig_bytes));
+       (size_t)(8 - png_ptr->sig_bytes));
 
    if (png_ptr->sig_bytes < 3)
       png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
@@ -124,8 +124,7 @@
  * given to png_write_chunk_header().
  */
 void PNGAPI
-png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,
-    png_size_t length)
+png_write_chunk_data(png_structrp png_ptr, png_const_bytep data, size_t length)
 {
    /* Write the data, and run the CRC over it */
    if (png_ptr == NULL)
@@ -160,7 +159,7 @@
    /* Write the crc in a single operation */
    png_save_uint_32(buf, png_ptr->crc);
 
-   png_write_data(png_ptr, buf, (png_size_t)4);
+   png_write_data(png_ptr, buf, 4);
 }
 
 /* Write a PNG chunk all at once.  The type is an array of ASCII characters
@@ -174,7 +173,7 @@
  */
 static void
 png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
-    png_const_bytep data, png_size_t length)
+    png_const_bytep data, size_t length)
 {
    if (png_ptr == NULL)
       return;
@@ -191,7 +190,7 @@
 /* This is the API that calls the internal function above. */
 void PNGAPI
 png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
-    png_const_bytep data, png_size_t length)
+    png_const_bytep data, size_t length)
 {
    png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
        length);
@@ -820,7 +819,7 @@
    buf[12] = (png_byte)interlace_type;
 
    /* Write the chunk */
-   png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
+   png_write_complete_chunk(png_ptr, png_IHDR, buf, 13);
 
    if ((png_ptr->do_filter) == PNG_NO_FILTERS)
    {
@@ -889,7 +888,7 @@
       buf[0] = pal_ptr->red;
       buf[1] = pal_ptr->green;
       buf[2] = pal_ptr->blue;
-      png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+      png_write_chunk_data(png_ptr, buf, 3);
    }
 
 #else
@@ -903,7 +902,7 @@
       buf[0] = pal_ptr[i].red;
       buf[1] = pal_ptr[i].green;
       buf[2] = pal_ptr[i].blue;
-      png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+      png_write_chunk_data(png_ptr, buf, 3);
    }
 
 #endif
@@ -1075,7 +1074,7 @@
 {
    png_debug(1, "in png_write_IEND");
 
-   png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
+   png_write_complete_chunk(png_ptr, png_IEND, NULL, 0);
    png_ptr->mode |= PNG_HAVE_IEND;
 }
 
@@ -1090,7 +1089,7 @@
 
    /* file_gamma is saved in 1/100,000ths */
    png_save_uint_32(buf, (png_uint_32)file_gamma);
-   png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
+   png_write_complete_chunk(png_ptr, png_gAMA, buf, 4);
 }
 #endif
 
@@ -1108,7 +1107,7 @@
           "Invalid sRGB rendering intent specified");
 
    buf[0]=(png_byte)srgb_intent;
-   png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
+   png_write_complete_chunk(png_ptr, png_sRGB, buf, 1);
 }
 #endif
 
@@ -1182,8 +1181,8 @@
    png_uint_32 name_len;
    png_byte new_name[80];
    png_byte entrybuf[10];
-   png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);
-   png_size_t palette_size = entry_size * (png_size_t)spalette->nentries;
+   size_t entry_size = (spalette->depth == 8 ? 6 : 10);
+   size_t palette_size = entry_size * (size_t)spalette->nentries;
    png_sPLT_entryp ep;
 #ifndef PNG_POINTER_INDEXING_SUPPORTED
    int i;
@@ -1200,10 +1199,9 @@
    png_write_chunk_header(png_ptr, png_sPLT,
        (png_uint_32)(name_len + 2 + palette_size));
 
-   png_write_chunk_data(png_ptr, (png_bytep)new_name,
-       (png_size_t)(name_len + 1));
+   png_write_chunk_data(png_ptr, (png_bytep)new_name, (size_t)(name_len + 1));
 
-   png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1);
+   png_write_chunk_data(png_ptr, &spalette->depth, 1);
 
    /* Loop through each palette entry, writing appropriately */
 #ifdef PNG_POINTER_INDEXING_SUPPORTED
@@ -1265,7 +1263,7 @@
 png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
 {
    png_byte buf[4];
-   png_size_t size;
+   size_t size;
 
    png_debug(1, "in png_write_sBIT");
 
@@ -1365,7 +1363,7 @@
 
       /* Write the chunk out as it is */
       png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
-          (png_size_t)num_trans);
+          (size_t)num_trans);
    }
 
    else if (color_type == PNG_COLOR_TYPE_GRAY)
@@ -1380,7 +1378,7 @@
       }
 
       png_save_uint_16(buf, tran->gray);
-      png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
+      png_write_complete_chunk(png_ptr, png_tRNS, buf, 2);
    }
 
    else if (color_type == PNG_COLOR_TYPE_RGB)
@@ -1400,7 +1398,7 @@
          return;
       }
 
-      png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
+      png_write_complete_chunk(png_ptr, png_tRNS, buf, 6);
    }
 
    else
@@ -1433,7 +1431,7 @@
       }
 
       buf[0] = back->index;
-      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, 1);
    }
 
    else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
@@ -1454,7 +1452,7 @@
          return;
       }
 
-      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, 6);
    }
 
    else
@@ -1468,7 +1466,7 @@
       }
 
       png_save_uint_16(buf, back->gray);
-      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, 2);
    }
 }
 #endif
@@ -1488,7 +1486,7 @@
    for (i = 0; i < num_exif; i++)
    {
       buf[0] = exif[i];
-      png_write_chunk_data(png_ptr, buf, (png_size_t)1);
+      png_write_chunk_data(png_ptr, buf, 1);
    }
 
    png_write_chunk_end(png_ptr);
@@ -1519,7 +1517,7 @@
    for (i = 0; i < num_hist; i++)
    {
       png_save_uint_16(buf, hist[i]);
-      png_write_chunk_data(png_ptr, buf, (png_size_t)2);
+      png_write_chunk_data(png_ptr, buf, 2);
    }
 
    png_write_chunk_end(png_ptr);
@@ -1530,7 +1528,7 @@
 /* Write a tEXt chunk */
 void /* PRIVATE */
 png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
-    png_size_t text_len)
+    size_t text_len)
 {
    png_uint_32 key_len;
    png_byte new_key[80];
@@ -1627,7 +1625,7 @@
     png_const_charp lang, png_const_charp lang_key, png_const_charp text)
 {
    png_uint_32 key_len, prefix_len;
-   png_size_t lang_len, lang_key_len;
+   size_t lang_len, lang_key_len;
    png_byte new_key[82];
    compression_state comp;
 
@@ -1737,7 +1735,7 @@
    png_save_int_32(buf + 4, y_offset);
    buf[8] = (png_byte)unit_type;
 
-   png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
+   png_write_complete_chunk(png_ptr, png_oFFs, buf, 9);
 }
 #endif
 #ifdef PNG_WRITE_pCAL_SUPPORTED
@@ -1748,7 +1746,7 @@
     png_charpp params)
 {
    png_uint_32 purpose_len;
-   png_size_t units_len, total_len;
+   size_t units_len, total_len;
    png_size_tp params_len;
    png_byte buf[10];
    png_byte new_purpose[80];
@@ -1772,7 +1770,7 @@
    total_len = purpose_len + units_len + 10;
 
    params_len = (png_size_tp)png_malloc(png_ptr,
-       (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (png_size_t))));
+       (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (size_t))));
 
    /* Find the length of each parameter, making sure we don't count the
     * null terminator for the last parameter.
@@ -1792,8 +1790,8 @@
    png_save_int_32(buf + 4, X1);
    buf[8] = (png_byte)type;
    buf[9] = (png_byte)nparams;
-   png_write_chunk_data(png_ptr, buf, (png_size_t)10);
-   png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);
+   png_write_chunk_data(png_ptr, buf, 10);
+   png_write_chunk_data(png_ptr, (png_const_bytep)units, (size_t)units_len);
 
    for (i = 0; i < nparams; i++)
    {
@@ -1812,7 +1810,7 @@
     png_const_charp height)
 {
    png_byte buf[64];
-   png_size_t wlen, hlen, total_len;
+   size_t wlen, hlen, total_len;
 
    png_debug(1, "in png_write_sCAL_s");
 
@@ -1853,7 +1851,7 @@
    png_save_uint_32(buf + 4, y_pixels_per_unit);
    buf[8] = (png_byte)unit_type;
 
-   png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
+   png_write_complete_chunk(png_ptr, png_pHYs, buf, 9);
 }
 #endif
 
@@ -1883,7 +1881,7 @@
    buf[5] = mod_time->minute;
    buf[6] = mod_time->second;
 
-   png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
+   png_write_complete_chunk(png_ptr, png_tIME, buf, 7);
 }
 #endif
 
@@ -2073,8 +2071,8 @@
       {
          if (png_ptr->prev_row != NULL)
             memset(png_ptr->prev_row, 0,
-                (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
-                png_ptr->usr_bit_depth, png_ptr->width)) + 1);
+                PNG_ROWBYTES(png_ptr->usr_channels *
+                png_ptr->usr_bit_depth, png_ptr->width) + 1);
 
          return;
       }
@@ -2130,7 +2128,7 @@
             for (i = png_pass_start[pass]; i < row_width;
                i += png_pass_inc[pass])
             {
-               sp = row + (png_size_t)(i >> 3);
+               sp = row + (size_t)(i >> 3);
                value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
                d |= (value << shift);
 
@@ -2168,7 +2166,7 @@
             for (i = png_pass_start[pass]; i < row_width;
                i += png_pass_inc[pass])
             {
-               sp = row + (png_size_t)(i >> 2);
+               sp = row + (size_t)(i >> 2);
                value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
                d |= (value << shift);
 
@@ -2204,7 +2202,7 @@
             for (i = png_pass_start[pass]; i < row_width;
                 i += png_pass_inc[pass])
             {
-               sp = row + (png_size_t)(i >> 1);
+               sp = row + (size_t)(i >> 1);
                value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
                d |= (value << shift);
 
@@ -2230,7 +2228,7 @@
             png_bytep dp;
             png_uint_32 i;
             png_uint_32 row_width = row_info->width;
-            png_size_t pixel_bytes;
+            size_t pixel_bytes;
 
             /* Start at the beginning */
             dp = row;
@@ -2243,7 +2241,7 @@
                i += png_pass_inc[pass])
             {
                /* Find out where the original pixel is */
-               sp = row + (png_size_t)i * pixel_bytes;
+               sp = row + (size_t)i * pixel_bytes;
 
                /* Move the pixel */
                if (dp != sp)
@@ -2274,16 +2272,16 @@
  */
 static void /* PRIVATE */
 png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
-    png_size_t row_bytes);
+    size_t row_bytes);
 
 #ifdef PNG_WRITE_FILTER_SUPPORTED
-static png_size_t /* PRIVATE */
+static size_t /* PRIVATE */
 png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
-    const png_size_t row_bytes, const png_size_t lmins)
+    size_t row_bytes, size_t lmins)
 {
    png_bytep rp, dp, lp;
-   png_size_t i;
-   png_size_t sum = 0;
+   size_t i;
+   size_t sum = 0;
    unsigned int v;
 
    png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
@@ -2318,10 +2316,10 @@
 
 static void /* PRIVATE */
 png_setup_sub_row_only(png_structrp png_ptr, const png_uint_32 bpp,
-    const png_size_t row_bytes)
+    size_t row_bytes)
 {
    png_bytep rp, dp, lp;
-   png_size_t i;
+   size_t i;
 
    png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
 
@@ -2338,13 +2336,12 @@
    }
 }
 
-static png_size_t /* PRIVATE */
-png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes,
-    const png_size_t lmins)
+static size_t /* PRIVATE */
+png_setup_up_row(png_structrp png_ptr, size_t row_bytes, size_t lmins)
 {
    png_bytep rp, dp, pp;
-   png_size_t i;
-   png_size_t sum = 0;
+   size_t i;
+   size_t sum = 0;
    unsigned int v;
 
    png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
@@ -2367,10 +2364,10 @@
    return (sum);
 }
 static void /* PRIVATE */
-png_setup_up_row_only(png_structrp png_ptr, const png_size_t row_bytes)
+png_setup_up_row_only(png_structrp png_ptr, size_t row_bytes)
 {
    png_bytep rp, dp, pp;
-   png_size_t i;
+   size_t i;
 
    png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
 
@@ -2382,13 +2379,13 @@
    }
 }
 
-static png_size_t /* PRIVATE */
+static size_t /* PRIVATE */
 png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
-    const png_size_t row_bytes, const png_size_t lmins)
+    size_t row_bytes, size_t lmins)
 {
    png_bytep rp, dp, pp, lp;
    png_uint_32 i;
-   png_size_t sum = 0;
+   size_t sum = 0;
    unsigned int v;
 
    png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
@@ -2424,7 +2421,7 @@
 }
 static void /* PRIVATE */
 png_setup_avg_row_only(png_structrp png_ptr, const png_uint_32 bpp,
-    const png_size_t row_bytes)
+    size_t row_bytes)
 {
    png_bytep rp, dp, pp, lp;
    png_uint_32 i;
@@ -2444,13 +2441,13 @@
    }
 }
 
-static png_size_t /* PRIVATE */
+static size_t /* PRIVATE */
 png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
-    const png_size_t row_bytes, const png_size_t lmins)
+    size_t row_bytes, size_t lmins)
 {
    png_bytep rp, dp, pp, cp, lp;
-   png_size_t i;
-   png_size_t sum = 0;
+   size_t i;
+   size_t sum = 0;
    unsigned int v;
 
    png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
@@ -2507,10 +2504,10 @@
 }
 static void /* PRIVATE */
 png_setup_paeth_row_only(png_structrp png_ptr, const png_uint_32 bpp,
-    const png_size_t row_bytes)
+    size_t row_bytes)
 {
    png_bytep rp, dp, pp, cp, lp;
-   png_size_t i;
+   size_t i;
 
    png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
 
@@ -2559,8 +2556,8 @@
    png_bytep row_buf;
    png_bytep best_row;
    png_uint_32 bpp;
-   png_size_t mins;
-   png_size_t row_bytes = row_info->rowbytes;
+   size_t mins;
+   size_t row_bytes = row_info->rowbytes;
 
    png_debug(1, "in png_write_find_filter");
 
@@ -2615,8 +2612,8 @@
        * 'none' filter.
        */
       png_bytep rp;
-      png_size_t sum = 0;
-      png_size_t i;
+      size_t sum = 0;
+      size_t i;
       unsigned int v;
 
       {
@@ -2644,8 +2641,8 @@
 
    else if ((filter_to_do & PNG_FILTER_SUB) != 0)
    {
-      png_size_t sum;
-      png_size_t lmins = mins;
+      size_t sum;
+      size_t lmins = mins;
 
       sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins);
 
@@ -2670,8 +2667,8 @@
 
    else if ((filter_to_do & PNG_FILTER_UP) != 0)
    {
-      png_size_t sum;
-      png_size_t lmins = mins;
+      size_t sum;
+      size_t lmins = mins;
 
       sum = png_setup_up_row(png_ptr, row_bytes, lmins);
 
@@ -2696,8 +2693,8 @@
 
    else if ((filter_to_do & PNG_FILTER_AVG) != 0)
    {
-      png_size_t sum;
-      png_size_t lmins = mins;
+      size_t sum;
+      size_t lmins = mins;
 
       sum= png_setup_avg_row(png_ptr, bpp, row_bytes, lmins);
 
@@ -2722,8 +2719,8 @@
 
    else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
    {
-      png_size_t sum;
-      png_size_t lmins = mins;
+      size_t sum;
+      size_t lmins = mins;
 
       sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins);
 
@@ -2748,7 +2745,7 @@
 /* Do the actual writing of a previously filtered row. */
 static void
 png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
-    png_size_t full_row_length/*includes filter byte*/)
+    size_t full_row_length/*includes filter byte*/)
 {
    png_debug(1, "in png_write_filtered_row");
 
diff --git a/powerpc/filter_vsx_intrinsics.c b/powerpc/filter_vsx_intrinsics.c
index e3de496..39521cf 100644
--- a/powerpc/filter_vsx_intrinsics.c
+++ b/powerpc/filter_vsx_intrinsics.c
@@ -42,8 +42,8 @@
    png_byte i;\
    png_bytep rp = row + offset;\
    png_const_bytep pp = prev_row;\
-   png_size_t unaligned_top = 16 - (((png_size_t)rp % 16));\
-   png_size_t istop;\
+   size_t unaligned_top = 16 - (((size_t)rp % 16));\
+   size_t istop;\
    if(unaligned_top == 16)\
       unaligned_top = 0;\
    istop = row_info->rowbytes;\