diff --git a/ANNOUNCE b/ANNOUNCE
index 0fdaeb6..7d208ad 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.4.0beta51 - March 21, 2009
+Libpng 1.4.0beta52 - March 28, 2009
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -9,27 +9,27 @@
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script
 
-   1.4.0beta51.tar.gz
-   1.4.0beta51.tar.bz2
+   1.4.0beta52.tar.gz
+   1.4.0beta52.tar.bz2
 
 Source files with LF line endings (for Unix/Linux) without the
 "configure" script
 
-   1.4.0beta51-no-config.tar.gz
-   1.4.0beta51-no-config.tar.bz2
+   1.4.0beta52-no-config.tar.gz
+   1.4.0beta52-no-config.tar.bz2
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   lp140b51.zip
-   lp140b51.tar.bz2
+   lp140b52.zip
+   lp140b52.tar.bz2
 
 Other information:
 
-   1.4.0beta51-README.txt
-   1.4.0beta51-KNOWNBUGS.txt
-   1.4.0beta51-LICENSE.txt
-   1.4.0beta51-Y2K-compliance.txt
+   1.4.0beta52-README.txt
+   1.4.0beta52-KNOWNBUGS.txt
+   1.4.0beta52-LICENSE.txt
+   1.4.0beta52-Y2K-compliance.txt
 
 Changes since the last public release (1.2.10):
 
@@ -343,7 +343,7 @@
   Added check for zero-area RGB cHRM triange in png_check_cHRM() and
     png_check_cHRM_fixed().
 
-version 1.4.0beta39 [March 21, 2009]
+version 1.4.0beta39 [November 23, 2008]
   Revised png_warning() to write its message on standard output by default
     when warning_fn is NULL.
 
@@ -392,7 +392,7 @@
     (bug introduced in libpng-1.2.34/1.4.0beta29).
   Revised comments in png_set_read_fn() and png_set_write_fn().
 
-version 1.4.0beta50 [March 21, 2009]
+version 1.4.0beta50 [March 18, 2009]
   Use png_calloc() instead of png_malloc() to allocate big_row_buf when
     reading an interlaced file, to avoid a possible UMR.
   Undid recent revision of PNG_NO_STDIO version of png_write_flush().  Users
@@ -406,6 +406,10 @@
 version 1.4.0beta51 [March 21, 2009]
   Removed new png_fileno() macro from pngconf.h .
 
+version 1.4.0beta52 [March 28, 2009]
+  Relocated png_do_chop() ahead of building gamma tables in pngrtran.c
+    This avoids building 16-bit gamma tables unnecessarily.
+
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.
 
diff --git a/CHANGES b/CHANGES
index d4fda86..94cfb02 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2068,7 +2068,7 @@
     (bug introduced in libpng-1.2.34/1.4.0beta29).
   Revised comments in png_set_read_fn() and png_set_write_fn().
 
-version 1.4.0beta50 [March 21, 2009]
+version 1.4.0beta50 [March 18, 2009]
   Use png_calloc() instead of png_malloc() to allocate big_row_buf when
     reading an interlaced file, to avoid a possible UMR.
   Undid revision of PNG_NO_STDIO version of png_write_flush().  Users
@@ -2082,6 +2082,10 @@
 version 1.4.0beta51 [March 21, 2009]
   Removed new png_fileno() macro from pngconf.h .
 
+version 1.4.0beta52 [March 28, 2009]
+  Relocated png_do_chop() ahead of building gamma tables in pngrtran.c
+    This avoids building 16-bit gamma tables unnecessarily.
+
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.
 
diff --git a/INSTALL b/INSTALL
index 054d0e2..26cf2aa 100644
--- a/INSTALL
+++ b/INSTALL
@@ -1,5 +1,5 @@
 
-Installing libpng version 1.4.0beta51 - March 21, 2009
+Installing libpng version 1.4.0beta52 - March 28, 2009
 
 On Unix/Linux and similar systems, you can simply type
 
@@ -44,7 +44,7 @@
 correspond to the version of zlib that's installed.
 
 You can rename the directories that you downloaded (they
-might be called "libpng-1.4.0beta51" or "lpng109" and "zlib-1.2.1"
+might be called "libpng-1.4.0beta52" or "lpng109" and "zlib-1.2.1"
 or "zlib121") so that you have directories called "zlib" and "libpng".
 
 Your directory structure should look like this:
@@ -95,14 +95,14 @@
  CMakeLists.txt    =>  "cmake" script
  makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
  makefile.elf      =>  Linux/ELF makefile symbol versioning,
-                       gcc, creates libpng14.so.14.1.4.0beta51)
+                       gcc, creates libpng14.so.14.1.4.0beta52)
  makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng14.so.14.1.4.0beta51)
+                       (gcc, creates libpng14.so.14.1.4.0beta52)
  makefile.gcmmx    =>  Linux/ELF makefile
-                       (gcc, creates libpng14.so.14.1.4.0beta51,
+                       (gcc, creates libpng14.so.14.1.4.0beta52,
                        uses assembler code tuned for Intel MMX platform)
  makefile.nommx    =>  Linux/ELF makefile
-                       (gcc, creates libpng14.so.14.1.4.0beta51
+                       (gcc, creates libpng14.so.14.1.4.0beta52
                        does not use Intel MMX assembler code)
  makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
  makefile.knr      =>  Archaic UNIX Makefile that converts files with
@@ -125,12 +125,12 @@
  makefile.openbsd  =>  OpenBSD makefile
  makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
  makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng14.so.14.1.4.0beta51)
+                       creates libpng14.so.14.1.4.0beta52)
  makefile.sunos    =>  Sun makefile
  makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng14.so.14.1.4.0beta51)
+                       creates libpng14.so.14.1.4.0beta52)
  makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng14.so.14.1.4.0beta51)
+                       creates libpng14.so.14.1.4.0beta52)
  makefile.32sunu   =>  Sun Ultra 32-bit makefile
  makefile.64sunu   =>  Sun Ultra 64-bit makefile
  makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
diff --git a/KNOWNBUG b/KNOWNBUG
index ba00d2b..668b185 100644
--- a/KNOWNBUG
+++ b/KNOWNBUG
@@ -1,5 +1,5 @@
 
-Known bugs in libpng version 1.4.0beta51
+Known bugs in libpng version 1.4.0beta52
 
 1. April 22, 2001: pnggccrd.c has been reported to crash on NetBSD when
    reading interlaced PNG files, when assembler code is enabled but running
diff --git a/LICENSE b/LICENSE
index 0f2e500..e2a4b1a 100644
--- a/LICENSE
+++ b/LICENSE
@@ -8,7 +8,7 @@
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.2.6, August 15, 2004, through 1.4.0beta51, March 21, 2009, are
+libpng versions 1.2.6, August 15, 2004, through 1.4.0beta52, March 28, 2009, are
 Copyright (c) 2004, 2006-2007 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -106,4 +106,4 @@
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-March 21, 2009
+March 28, 2009
diff --git a/Makefile.am b/Makefile.am
index 9329f65..8785ca4 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -86,7 +86,7 @@
 	${srcdir}/contrib/pngsuite/* \
 	${srcdir}/contrib/visupng/* \
 	$(TESTS) \
-	example.c libpng-1.4.0beta51.txt pngvcrd.c 
+	example.c libpng-1.4.0beta52.txt pngvcrd.c 
 
 CLEANFILES= pngout.png libpng14.pc libpng14-config libpng.vers \
 libpng.sym
diff --git a/Makefile.in b/Makefile.in
index 8cf7ac2..ab7ce87 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -331,7 +331,7 @@
 	${srcdir}/contrib/pngsuite/* \
 	${srcdir}/contrib/visupng/* \
 	$(TESTS) \
-	example.c libpng-1.4.0beta51.txt pngvcrd.c 
+	example.c libpng-1.4.0beta52.txt pngvcrd.c 
 
 CLEANFILES = pngout.png libpng14.pc libpng14-config libpng.vers \
 libpng.sym
diff --git a/README b/README
index d3ad9bb..47b61f0 100644
--- a/README
+++ b/README
@@ -1,4 +1,4 @@
-README for libpng version 1.4.0beta51 - March 21, 2009 (shared library 14.0)
+README for libpng version 1.4.0beta52 - March 28, 2009 (shared library 14.0)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.
@@ -184,11 +184,11 @@
        descrip.mms      =>  VMS makefile for MMS or MMK
        makefile.std     =>  Generic UNIX makefile (cc, creates static libpng.a)
        makefile.elf     =>  Linux/ELF makefile symbol versioning,
-                            gcc, creates libpng14.so.14.1.4.0beta51)
+                            gcc, creates libpng14.so.14.1.4.0beta52)
        makefile.linux   =>  Linux/ELF makefile
-                            (gcc, creates libpng14.so.14.1.4.0beta51)
+                            (gcc, creates libpng14.so.14.1.4.0beta52)
        makefile.gcmmx   =>  Linux/ELF makefile
-                            (gcc, creates libpng14.so.14.1.4.0beta51,
+                            (gcc, creates libpng14.so.14.1.4.0beta52,
                             uses assembler code tuned for Intel MMX platform)
        makefile.gcc     =>  Generic makefile (gcc, creates static libpng.a)
        makefile.knr     =>  Archaic UNIX Makefile that converts files with
@@ -210,12 +210,12 @@
        makefile.openbsd =>  OpenBSD makefile
        makefile.sgi     =>  Silicon Graphics IRIX (cc, creates static lib)
        makefile.sggcc   =>  Silicon Graphics
-                            (gcc, creates libpng14.so.14.1.4.0beta51)
+                            (gcc, creates libpng14.so.14.1.4.0beta52)
        makefile.sunos   =>  Sun makefile
        makefile.solaris =>  Solaris 2.X makefile
-                            (gcc, creates libpng14.so.14.1.4.0beta51)
+                            (gcc, creates libpng14.so.14.1.4.0beta52)
        makefile.so9     =>  Solaris 9 makefile
-                            (gcc, creates libpng14.so.14.1.4.0beta51)
+                            (gcc, creates libpng14.so.14.1.4.0beta52)
        makefile.32sunu  =>  Sun Ultra 32-bit makefile
        makefile.64sunu  =>  Sun Ultra 64-bit makefile
        makefile.sco     =>  For SCO OSr5  ELF and Unixware 7 with Native cc
diff --git a/configure b/configure
index af527d9..5b6eb82 100755
--- a/configure
+++ b/configure
Binary files differ
diff --git a/configure.ac b/configure.ac
index 46c8a54..0745579 100644
--- a/configure.ac
+++ b/configure.ac
@@ -18,12 +18,12 @@
 
 dnl Version number stuff here:
 
-AC_INIT([libpng], [1.4.0beta51], [png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng], [1.4.0beta52], [png-mng-implement@lists.sourceforge.net])
 AM_INIT_AUTOMAKE
 dnl stop configure from automagically running automake
 AM_MAINTAINER_MODE
 
-PNGLIB_VERSION=1.4.0beta51
+PNGLIB_VERSION=1.4.0beta52
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=4
 PNGLIB_RELEASE=0
diff --git a/contrib/gregbook/Makefile.sgi b/contrib/gregbook/Makefile.sgi
index e3ca6ce..3a5044a 100644
--- a/contrib/gregbook/Makefile.sgi
+++ b/contrib/gregbook/Makefile.sgi
@@ -23,9 +23,9 @@
 
 # macros --------------------------------------------------------------------
 
-PNGINC = -I/usr/local/include/libpng12
-PNGLIB = -L/usr/local/lib -lpng12	  # dynamically linked against libpng
-#PNGLIB = /usr/local/lib/libpng12.a # statically linked against libpng
+PNGINC = -I/usr/local/include/libpng%NN%
+PNGLIB = -L/usr/local/lib -lpng%NN%	  # dynamically linked against libpng
+#PNGLIB = /usr/local/lib/libpng%NN%.a # statically linked against libpng
 # or:
 #PNGINC = -I../..
 #PNGLIB = -L../.. -lpng
diff --git a/contrib/gregbook/Makefile.unx b/contrib/gregbook/Makefile.unx
index 7ff65bf..3c08719 100644
--- a/contrib/gregbook/Makefile.unx
+++ b/contrib/gregbook/Makefile.unx
@@ -26,14 +26,14 @@
 # macros --------------------------------------------------------------------
 
 #PNGDIR = /usr/local/lib
-#PNGINC = -I/usr/local/include/libpng12
-#PNGLIBd = -L$(PNGDIR) -lpng12 # dynamically linked, installed libpng
-#PNGLIBs = $(PNGDIR)/libpng12.a # statically linked, installed libpng
+#PNGINC = -I/usr/local/include/libpng%NN%
+#PNGLIBd = -L$(PNGDIR) -lpng%NN% # dynamically linked, installed libpng
+#PNGLIBs = $(PNGDIR)/libpng%NN%.a # statically linked, installed libpng
 # or:
 PNGDIR = ../..#	this one is for libpng-x.y.z/contrib/gregbook builds
 #PNGDIR = ../libpng
 PNGINC = -I$(PNGDIR)
-PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng12	# dynamically linked
+PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng%NN%	# dynamically linked
 PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
 
 ZDIR = /usr/local/lib
diff --git a/contrib/gregbook/readpng.c b/contrib/gregbook/readpng.c
index d87f6c7..abfc1fb 100644
--- a/contrib/gregbook/readpng.c
+++ b/contrib/gregbook/readpng.c
@@ -93,7 +93,7 @@
      * have used slightly more general png_sig_cmp() function instead */
 
     fread(sig, 1, 8, infile);
-    if (!png_check_sig(sig, 8))
+    if (png_sig_cmp(sig, 0, 8))
         return 1;   /* bad signature */
 
 
diff --git a/contrib/gregbook/readpng2.c b/contrib/gregbook/readpng2.c
index 9215042..0874b0a 100644
--- a/contrib/gregbook/readpng2.c
+++ b/contrib/gregbook/readpng2.c
@@ -159,7 +159,7 @@
 
 int readpng2_check_sig(uch *sig, int num)
 {
-    return png_check_sig(sig, num);
+    return (!png_sig_cmp(sig, 0, num));
 }
 
 
diff --git a/example.c b/example.c
index ffc8da2..f55e4f2 100644
--- a/example.c
+++ b/example.c
@@ -2,7 +2,7 @@
 #if 0 /* in case someone actually tries to compile this */
 
 /* example.c - an example of using libpng
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * This file has been placed in the public domain by the authors.
  * Maintained 1998-2009 Glenn Randers-Pehrson
  * Maintained 1996, 1997 Andreas Dilger)
diff --git a/libpng-1.4.0beta51.txt b/libpng-1.4.0beta52.txt
similarity index 95%
rename from libpng-1.4.0beta51.txt
rename to libpng-1.4.0beta52.txt
index b974dc7..3fb4150 100644
--- a/libpng-1.4.0beta51.txt
+++ b/libpng-1.4.0beta52.txt
@@ -1,6 +1,6 @@
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.4.0beta51 - March 21, 2009
+ libpng version 1.4.0beta52 - March 28, 2009
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2009 Glenn Randers-Pehrson
@@ -9,7 +9,7 @@
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.4.0beta51 - March 21, 2009
+ libpng versions 0.97, January 1998, through 1.4.0beta52 - March 28, 2009
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2008 Glenn Randers-Pehrson
 
@@ -141,9 +141,10 @@
 will also want to insure that you are, in fact, dealing with a PNG
 file.  Libpng provides a simple check to see if a file is a PNG file.
 To use it, pass in the first 1 to 8 bytes of the file to the function
-png_sig_cmp(), and it will return 0 if the bytes match the corresponding
-bytes of the PNG signature, or nonzero otherwise.  Of course, the more bytes
-you pass in, the greater the accuracy of the prediction.
+png_sig_cmp(), and it will return 0 (false) if the bytes match the
+corresponding bytes of the PNG signature, or nonzero (true) otherwise.
+Of course, the more bytes you pass in, the greater the accuracy of the
+prediction.
 
 If you are intending to keep the file pointer open for use in libpng,
 you must ensure you don't read more than 8 bytes from the beginning
@@ -882,7 +883,7 @@
 As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
 added.  It expands the sample depth without changing tRNS to alpha.
 
-As of libpng version 1.4.0beta51, not all possible expansions are supported.
+As of libpng version 1.4.0beta52, not all possible expansions are supported.
 
 In the following table, the 01 means grayscale with depth<8, 31 means
 indexed with depth<8, other numerals represent the color type, "T" means
@@ -2904,15 +2905,153 @@
 
    png_uint_32 application_vn = PNG_LIBPNG_VER;
 
-VIII. Y2K Compliance in libpng
+VIII.  Changes to Libpng from version 1.0.x to 1.2.x
 
-March 21, 2009
+Support for user memory management was enabled by default.  To
+accomplish this, the functions png_create_read_struct_2(),
+png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
+png_malloc_default(), and png_free_default() were added.
+
+Support for certain MNG features was enabled.
+
+Support for numbered error messages was added.  However, we never got
+around to actually numbering the error messages.  The function
+png_set_strip_error_numbers() was added (Note: the prototype for this
+function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
+builds of libpng-1.2.15.  It was restored in libpng-1.2.36).
+
+The png_malloc_warn() function was added at libpng-1.2.3.  This issues
+a png_warning and returns NULL instead of aborting when it fails to
+acquire the requested memory allocation.
+
+Support for setting user limits on image width and height was enabled
+by default.  The functions png_set_user_limits(), png_get_user_width_max(),
+and png_get_user_height_max() were added at libpng-1.2.6.
+
+The png_set_add_alpha() function was added at libpng-1.2.7.
+
+The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
+Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
+tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
+deprecated.
+
+A number of macro definitions in support of runtime selection of
+assembler code features (especially Intel MMX code support) were
+added at libpng-1.2.0:
+
+    PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
+    PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+    PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
+    PNG_ASM_FLAG_MMX_READ_INTERLACE
+    PNG_ASM_FLAG_MMX_READ_FILTER_SUB
+    PNG_ASM_FLAG_MMX_READ_FILTER_UP
+    PNG_ASM_FLAG_MMX_READ_FILTER_AVG
+    PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
+    PNG_ASM_FLAGS_INITIALIZED
+    PNG_MMX_READ_FLAGS
+    PNG_MMX_FLAGS
+    PNG_MMX_WRITE_FLAGS
+    PNG_MMX_FLAGS
+
+We added the following functions in support of runtime
+selection of assembler code features:
+
+    png_get_mmx_flagmask()
+    png_set_mmx_thresholds()
+    png_get_asm_flags()
+    png_get_mmx_bitdepth_threshold()
+    png_get_mmx_rowbytes_threshold()
+    png_set_asm_flags()
+
+We replaced all of these functions with simple stubs in libpng-1.2.20,
+when the Intel assembler code was removed due to a licensing issue.
+
+IX.  Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+
+Private libpng prototypes and macro definitions were moved from
+png.h and pngconf.h into a new pngpriv.h header file.
+
+Support for the iTXt chunk has been enabled by default.
+
+Support for global arrays was disabled by default.
+
+Some obsolete/deprecated macros and functions have been removed.
+
+The PNG_1_0_X and PNG_1_2_X macros were eliminated.
+
+Many WIN32_WCE #ifdefs were removed.
+
+PNG_MAX_UINT was replaced with PNG_UINT_31_MAX.  It has been
+deprecated since libpng-1.0.16 and libpng-1.2.6.
+
+The function
+    png_check_sig(sig, num)
+was replaced with
+    !png_sig_cmp(sig, 0, num)
+It has been deprecated since libpng-0.90.
+
+The functions png_read_init(info_ptr), png_write_init(info_ptr),
+png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
+have been removed.  They have been deprecated since libpng-0.95.
+
+The function
+    png_set_gray_1_2_4_to_8()
+which also expands tRNS to alpha was replaced with
+    png_set_expand_gray_1_2_4_to_8()
+which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
+
+Support for numbered error messages was removed by default, since we
+never got around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was removed from the library by default.
+
+Functions png_set_benign_errors(), png_benign_error(), and
+png_chunk_benign_error() were added.
+
+Support for setting the maximum amount of memory that the application
+will allocate for reading chunks was added, as a security measure.
+The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
+were added to the library.
+
+We implemented support for I/O states. Added png_ptr member io_state, and
+functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+
+The png_permit_empty_plte() was removed. It has been deprecated
+since libpng-1.0.9.  Use png_permit_mng_features() instead.
+
+We removed the obsolete stub functions png_get_mmx_flagmask(),
+png_set_mmx_thresholds(), png_get_asm_flags(),
+png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
+png_set_asm_flags(), and png_mmx_supported()
+
+We removed the png_memcpy_check() and png_memset_check() functions.
+
+We changed the prototype for png_malloc() from
+    png_malloc(png_structp png_ptr, png_uint_32 size)
+to
+    png_malloc(png_structp png_ptr, png_alloc_size_t size)
+
+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_uint_32.
+
+The png_zalloc() function no longer zeroes out the memory that it
+allocates.
+
+The png_zalloc() and png_zfree() functions are no longer exported.
+
+The png_calloc() function was added.
+
+We removed the trailing '.' from the warning and error messages.
+
+X. Y2K Compliance in libpng
+
+March 28, 2009
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.4.0beta51 are Y2K compliant.  It is my belief that earlier
+upward through 1.4.0beta52 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that
diff --git a/libpng.3 b/libpng.3
index 3131eea..d1419b1 100644
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "March 21, 2009"
+.TH LIBPNG 3 "March 28, 2009"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.4.0beta51
+libpng \- Portable Network Graphics (PNG) Reference Library 1.4.0beta52
 .SH SYNOPSIS
 \fI\fB
 
@@ -809,7 +809,7 @@
 .SH LIBPNG.TXT
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.4.0beta51 - March 21, 2009
+ libpng version 1.4.0beta52 - March 28, 2009
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2009 Glenn Randers-Pehrson
@@ -818,7 +818,7 @@
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.4.0beta51 - March 21, 2009
+ libpng versions 0.97, January 1998, through 1.4.0beta52 - March 28, 2009
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2008 Glenn Randers-Pehrson
 
@@ -950,9 +950,10 @@
 will also want to insure that you are, in fact, dealing with a PNG
 file.  Libpng provides a simple check to see if a file is a PNG file.
 To use it, pass in the first 1 to 8 bytes of the file to the function
-png_sig_cmp(), and it will return 0 if the bytes match the corresponding
-bytes of the PNG signature, or nonzero otherwise.  Of course, the more bytes
-you pass in, the greater the accuracy of the prediction.
+png_sig_cmp(), and it will return 0 (false) if the bytes match the
+corresponding bytes of the PNG signature, or nonzero (true) otherwise.
+Of course, the more bytes you pass in, the greater the accuracy of the
+prediction.
 
 If you are intending to keep the file pointer open for use in libpng,
 you must ensure you don't read more than 8 bytes from the beginning
@@ -1691,7 +1692,7 @@
 As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
 added.  It expands the sample depth without changing tRNS to alpha.
 
-As of libpng version 1.4.0beta51, not all possible expansions are supported.
+As of libpng version 1.4.0beta52, not all possible expansions are supported.
 
 In the following table, the 01 means grayscale with depth<8, 31 means
 indexed with depth<8, other numerals represent the color type, "T" means
@@ -3713,15 +3714,153 @@
 
    png_uint_32 application_vn = PNG_LIBPNG_VER;
 
-.SH VIII. Y2K Compliance in libpng
+.SH VIII.  Changes to Libpng from version 1.0.x to 1.2.x
 
-March 21, 2009
+Support for user memory management was enabled by default.  To
+accomplish this, the functions png_create_read_struct_2(),
+png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
+png_malloc_default(), and png_free_default() were added.
+
+Support for certain MNG features was enabled.
+
+Support for numbered error messages was added.  However, we never got
+around to actually numbering the error messages.  The function
+png_set_strip_error_numbers() was added (Note: the prototype for this
+function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
+builds of libpng-1.2.15.  It was restored in libpng-1.2.36).
+
+The png_malloc_warn() function was added at libpng-1.2.3.  This issues
+a png_warning and returns NULL instead of aborting when it fails to
+acquire the requested memory allocation.
+
+Support for setting user limits on image width and height was enabled
+by default.  The functions png_set_user_limits(), png_get_user_width_max(),
+and png_get_user_height_max() were added at libpng-1.2.6.
+
+The png_set_add_alpha() function was added at libpng-1.2.7.
+
+The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
+Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
+tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
+deprecated.
+
+A number of macro definitions in support of runtime selection of
+assembler code features (especially Intel MMX code support) were
+added at libpng-1.2.0:
+
+    PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
+    PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+    PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
+    PNG_ASM_FLAG_MMX_READ_INTERLACE
+    PNG_ASM_FLAG_MMX_READ_FILTER_SUB
+    PNG_ASM_FLAG_MMX_READ_FILTER_UP
+    PNG_ASM_FLAG_MMX_READ_FILTER_AVG
+    PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
+    PNG_ASM_FLAGS_INITIALIZED
+    PNG_MMX_READ_FLAGS
+    PNG_MMX_FLAGS
+    PNG_MMX_WRITE_FLAGS
+    PNG_MMX_FLAGS
+
+We added the following functions in support of runtime
+selection of assembler code features:
+
+    png_get_mmx_flagmask()
+    png_set_mmx_thresholds()
+    png_get_asm_flags()
+    png_get_mmx_bitdepth_threshold()
+    png_get_mmx_rowbytes_threshold()
+    png_set_asm_flags()
+
+We replaced all of these functions with simple stubs in libpng-1.2.20,
+when the Intel assembler code was removed due to a licensing issue.
+
+.SH IX.  Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+
+Private libpng prototypes and macro definitions were moved from
+png.h and pngconf.h into a new pngpriv.h header file.
+
+Support for the iTXt chunk has been enabled by default.
+
+Support for global arrays was disabled by default.
+
+Some obsolete/deprecated macros and functions have been removed.
+
+The PNG_1_0_X and PNG_1_2_X macros were eliminated.
+
+Many WIN32_WCE #ifdefs were removed.
+
+PNG_MAX_UINT was replaced with PNG_UINT_31_MAX.  It has been
+deprecated since libpng-1.0.16 and libpng-1.2.6.
+
+The function
+    png_check_sig(sig, num)
+was replaced with
+    !png_sig_cmp(sig, 0, num)
+It has been deprecated since libpng-0.90.
+
+The functions png_read_init(info_ptr), png_write_init(info_ptr),
+png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
+have been removed.  They have been deprecated since libpng-0.95.
+
+The function
+    png_set_gray_1_2_4_to_8()
+which also expands tRNS to alpha was replaced with
+    png_set_expand_gray_1_2_4_to_8()
+which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
+
+Support for numbered error messages was removed by default, since we
+never got around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was removed from the library by default.
+
+Functions png_set_benign_errors(), png_benign_error(), and
+png_chunk_benign_error() were added.
+
+Support for setting the maximum amount of memory that the application
+will allocate for reading chunks was added, as a security measure.
+The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
+were added to the library.
+
+We implemented support for I/O states. Added png_ptr member io_state, and
+functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+
+The png_permit_empty_plte() was removed. It has been deprecated
+since libpng-1.0.9.  Use png_permit_mng_features() instead.
+
+We removed the obsolete stub functions png_get_mmx_flagmask(),
+png_set_mmx_thresholds(), png_get_asm_flags(),
+png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
+png_set_asm_flags(), and png_mmx_supported()
+
+We removed the png_memcpy_check() and png_memset_check() functions.
+
+We changed the prototype for png_malloc() from
+    png_malloc(png_structp png_ptr, png_uint_32 size)
+to
+    png_malloc(png_structp png_ptr, png_alloc_size_t size)
+
+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_uint_32.
+
+The png_zalloc() function no longer zeroes out the memory that it
+allocates.
+
+The png_zalloc() and png_zfree() functions are no longer exported.
+
+The png_calloc() function was added.
+
+We removed the trailing '.' from the warning and error messages.
+
+.SH X. Y2K Compliance in libpng
+
+March 28, 2009
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.4.0beta51 are Y2K compliant.  It is my belief that earlier
+upward through 1.4.0beta52 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that
@@ -3889,7 +4028,7 @@
  1.4.0beta9-14       14    10400  14.so.0.0[.0]
  1.2.13              13    10213  12.so.0.13[.0]
  1.4.0beta15-36      14    10400  14.so.0.0[.0]
- 1.4.0beta37-51      14    10400  14.so.14.0[.0]
+ 1.4.0beta37-52      14    10400  14.so.14.0[.0]
 
 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -3945,7 +4084,7 @@
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
 
-Libpng version 1.4.0beta51 - March 21, 2009:
+Libpng version 1.4.0beta52 - March 28, 2009:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
 
@@ -3966,7 +4105,7 @@
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.2.6, August 15, 2004, through 1.4.0beta51, March 21, 2009, are
+libpng versions 1.2.6, August 15, 2004, through 1.4.0beta52, March 28, 2009, are
 Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -4065,7 +4204,7 @@
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-March 21, 2009
+March 28, 2009
 
 .\" end of man page
 
diff --git a/libpngpf.3 b/libpngpf.3
index 158567d..99b1f08 100644
--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "March 21, 2009"
+.TH LIBPNGPF 3 "March 28, 2009"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.4.0beta51
+libpng \- Portable Network Graphics (PNG) Reference Library 1.4.0beta52
 (private functions)
 .SH SYNOPSIS
 \fB#include <png.h>\fP
diff --git a/png.5 b/png.5
index 4ad8aa6..e21f918 100644
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "March 21, 2009"
+.TH PNG 5 "March 28, 2009"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
diff --git a/png.c b/png.c
index 03ae770..c538744 100644
--- a/png.c
+++ b/png.c
@@ -1,7 +1,7 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -13,7 +13,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_4_0beta51 Your_png_h_is_not_version_1_4_0beta51;
+typedef version_1_4_0beta52 Your_png_h_is_not_version_1_4_0beta52;
 
 /* Version information for C files.  This had better match the version
  * string defined in png.h.  */
@@ -641,13 +641,13 @@
 #else
 #ifdef __STDC__
    return ((png_charp) PNG_STRING_NEWLINE \
-     "libpng version x 1.4.0beta51 - March 21, 2009" PNG_STRING_NEWLINE \
+     "libpng version x 1.4.0beta52 - March 28, 2009" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2009 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
      PNG_STRING_NEWLINE);
 #else
-      return ((png_charp) "libpng version 1.4.0beta51 - March 21, 2009\
+      return ((png_charp) "libpng version 1.4.0beta52 - March 28, 2009\
       Copyright (c) 1998-2009 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.");
diff --git a/png.h b/png.h
index 275525e..dc1f40a 100644
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.4.0beta51 - March 21, 2009
+ * libpng version 1.4.0beta52 - March 28, 2009
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -9,7 +9,7 @@
  * Authors and maintainers:
  *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *  libpng versions 0.97, January 1998, through 1.4.0beta51 - March 21, 2009: Glenn
+ *  libpng versions 0.97, January 1998, through 1.4.0beta52 - March 28, 2009: Glenn
  *  See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -127,7 +127,7 @@
  *    1.4.0beta9-14           14    10400  14.so.0.0[.0]
  *    1.2.13                  13    10213  12.so.0.10[.0]
  *    1.4.0beta15-36          14    10400  14.so.0.0[.0]
- *    1.4.0beta37-51          14    10400  14.so.14.0[.0]
+ *    1.4.0beta37-52          14    10400  14.so.14.0[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
@@ -157,7 +157,7 @@
  * If you modify libpng you may insert additional notices immediately following
  * this sentence.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.4.0beta51, March 21, 2009, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.4.0beta52, March 28, 2009, are
  * Copyright (c) 2004, 2006-2007 Glenn Randers-Pehrson, and are
  * distributed according to the same disclaimer and license as libpng-1.2.5
  * with the following individual added to the list of Contributing Authors:
@@ -275,7 +275,7 @@
  *    an official declaration.
  *
  *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.4.0beta51 are Y2K compliant.  It is my belief that earlier
+ *    upward through 1.4.0beta52 are Y2K compliant.  It is my belief that earlier
  *    versions were also Y2K compliant.
  *
  *    Libpng only has three year fields.  One is a 2-byte unsigned integer
@@ -331,9 +331,9 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.4.0beta51"
+#define PNG_LIBPNG_VER_STRING "1.4.0beta52"
 #define PNG_HEADER_VERSION_STRING \
-   " libpng version 1.4.0beta51 - March 21, 2009\n"
+   " libpng version 1.4.0beta52 - March 28, 2009\n"
 
 #define PNG_LIBPNG_VER_SONUM   14
 #define PNG_LIBPNG_VER_DLLNUM  14
@@ -345,7 +345,7 @@
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero: */
 
-#define PNG_LIBPNG_VER_BUILD  51
+#define PNG_LIBPNG_VER_BUILD  52
 
 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -1356,7 +1356,7 @@
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef png_structp version_1_4_0beta51;
+typedef png_structp version_1_4_0beta52;
 
 typedef png_struct FAR * FAR * png_structpp;
 
@@ -2509,7 +2509,6 @@
    png_ptr, png_uint_32 strip_mode));
 #endif
 
-
 /* Added in libpng-1.2.6 */
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
 extern PNG_EXPORT(void,png_set_user_limits) PNGARG((png_structp
diff --git a/pngconf.h b/pngconf.h
index 483d1b7..f3a1514 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.4.0beta51 - March 21, 2009
+ * libpng version 1.4.0beta52 - March 28, 2009
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -1046,7 +1046,7 @@
 #define png_sizeof(x) sizeof(x)
 
 /* The following is needed for medium model support.  It cannot be in the
- * PNG_INTERNAL section.  Needs modification for other compilers besides
+ * pngpriv.h header.  Needs modification for other compilers besides
  * MSC.  Model independent support declares all arrays and pointers to be
  * large using the far keyword.  The zlib version used must also support
  * model independent data.  As of version zlib 1.0.4, the necessary changes
diff --git a/pngerror.c b/pngerror.c
index f98e1f2..0820cd7 100644
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,7 +1,7 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngget.c b/pngget.c
index 306b292..294c75f 100644
--- a/pngget.c
+++ b/pngget.c
@@ -1,7 +1,7 @@
 
 /* pngget.c - retrieval of values from info struct
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngmem.c b/pngmem.c
index edc0152..75751b3 100644
--- a/pngmem.c
+++ b/pngmem.c
@@ -1,7 +1,7 @@
 
 /* pngmem.c - stub functions for memory allocation
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngpread.c b/pngpread.c
index d1806a7..7b187cd 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,7 +1,7 @@
 
 /* pngpread.c - read a png file in push mode
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngpriv.h b/pngpriv.h
index 1163e31..5b9502e 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -1,7 +1,7 @@
 
 /* pngpriv.h - private declarations for use inside libpng
  *
- * libpng version 1.4.0beta51 - March 21, 2009
+ * libpng version 1.4.0beta52 - March 28, 2009
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngread.c b/pngread.c
index 42b2e64..af0e0cd 100644
--- a/pngread.c
+++ b/pngread.c
@@ -1,7 +1,7 @@
 
 /* pngread.c - read a PNG file
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngrio.c b/pngrio.c
index 5b4b54a..434b27b 100644
--- a/pngrio.c
+++ b/pngrio.c
@@ -1,7 +1,7 @@
 
 /* pngrio.c - functions for data input
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngrtran.c b/pngrtran.c
index 9335c91..51c4872 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1,7 +1,7 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -1380,6 +1380,11 @@
       png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+   if (png_ptr->transformations & PNG_16_TO_8)
+      png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
    if ((png_ptr->transformations & PNG_BACKGROUND) &&
       ((png_ptr->num_trans != 0 ) ||
@@ -1409,11 +1414,6 @@
          png_ptr->gamma_shift);
 #endif
 
-#if defined(PNG_READ_16_TO_8_SUPPORTED)
-   if (png_ptr->transformations & PNG_16_TO_8)
-      png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
-#endif
-
 #if defined(PNG_READ_DITHER_SUPPORTED)
    if (png_ptr->transformations & PNG_DITHER)
    {
diff --git a/pngrutil.c b/pngrutil.c
index e1a4190..61a069a 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,7 +1,7 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngset.c b/pngset.c
index f6a9c38..699c16f 100644
--- a/pngset.c
+++ b/pngset.c
@@ -1,7 +1,7 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngtest.c b/pngtest.c
index 3038a7c..dd75817 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,7 +1,7 @@
 
 /* pngtest.c - a simple test program to test libpng
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -1611,4 +1611,4 @@
 }
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_4_0beta51 your_png_h_is_not_version_1_4_0beta51;
+typedef version_1_4_0beta52 your_png_h_is_not_version_1_4_0beta52;
diff --git a/pngtrans.c b/pngtrans.c
index c6d0a84..2bba86c 100644
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,7 +1,7 @@
 
 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -126,7 +126,6 @@
    }
 }
 
-#if !defined(PNG_1_0_X)
 /* Added to libpng-1.2.7 */
 void PNGAPI
 png_set_add_alpha(png_structp png_ptr, png_uint_32 filler, int filler_loc)
@@ -136,7 +135,6 @@
    png_set_filler(png_ptr, filler, filler_loc);
    png_ptr->transformations |= PNG_ADD_ALPHA;
 }
-#endif
 
 #endif
 
diff --git a/pngwio.c b/pngwio.c
index 29cb010..273df02 100644
--- a/pngwio.c
+++ b/pngwio.c
@@ -1,7 +1,7 @@
 
 /* pngwio.c - functions for data output
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngwrite.c b/pngwrite.c
index f5ce493..cf3ea86 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,7 +1,7 @@
 
 /* pngwrite.c - general routines to write a PNG file
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngwtran.c b/pngwtran.c
index 6b44196..7740123 100644
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -1,7 +1,7 @@
 
 /* pngwtran.c - transforms the data in a row for PNG writers
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngwutil.c b/pngwutil.c
index ad9f29b..f5e2253 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@
 
 /* pngwutil.c - utilities to write a PNG file
  *
- * Last changed in libpng 1.4.0 [March 21, 2009]
+ * Last changed in libpng 1.4.0 [March 28, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/scripts/CMakeLists.txt b/scripts/CMakeLists.txt
index 46d70b5..277f8a5 100644
--- a/scripts/CMakeLists.txt
+++ b/scripts/CMakeLists.txt
@@ -178,7 +178,7 @@
 
 # SET UP LINKS
 set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#    VERSION 0.${PNGLIB_RELEASE}.1.4.0beta51
+#    VERSION 0.${PNGLIB_RELEASE}.1.4.0beta52
      VERSION 0.${PNGLIB_RELEASE}.0
      SOVERSION 0
      CLEAN_DIRECT_OUTPUT 1)
diff --git a/scripts/libpng-config-head.in b/scripts/libpng-config-head.in
index 6da2168..d60d28e 100755
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -8,7 +8,7 @@
 
 # Modeled after libxml-config.
 
-version=1.4.0beta51
+version=1.4.0beta52
 prefix=""
 libdir=""
 libs=""
diff --git a/scripts/libpng.pc.in b/scripts/libpng.pc.in
index 4f4d1c4..b8632db 100644
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -5,6 +5,6 @@
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.4.0beta51
+Version: 1.4.0beta52
 Libs: -L${libdir} -lpng14
 Cflags: -I${includedir}
diff --git a/scripts/makefile.32sunu b/scripts/makefile.32sunu
index 498b4fb..8b9c88c 100644
--- a/scripts/makefile.32sunu
+++ b/scripts/makefile.32sunu
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.64sunu b/scripts/makefile.64sunu
index 919b528..c030ad1 100644
--- a/scripts/makefile.64sunu
+++ b/scripts/makefile.64sunu
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.aix b/scripts/makefile.aix
index 085b335..05a4b18 100644
--- a/scripts/makefile.aix
+++ b/scripts/makefile.aix
@@ -20,7 +20,7 @@
 
 LIBNAME=libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 prefix=/usr/local
diff --git a/scripts/makefile.beos b/scripts/makefile.beos
index 5d227ff..b694aa2 100644
--- a/scripts/makefile.beos
+++ b/scripts/makefile.beos
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.cygwin b/scripts/makefile.cygwin
index 19aab83..b62dcd3 100644
--- a/scripts/makefile.cygwin
+++ b/scripts/makefile.cygwin
@@ -65,7 +65,7 @@
 LIBNAME = libpng14
 PNGMAJ = 14
 CYGDLL = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=cygpng$(CYGDLL).dll
diff --git a/scripts/makefile.darwin b/scripts/makefile.darwin
index 3fc9ef6..2328057 100644
--- a/scripts/makefile.darwin
+++ b/scripts/makefile.darwin
@@ -19,7 +19,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 12
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.dec b/scripts/makefile.dec
index 2329486..48d3772 100644
--- a/scripts/makefile.dec
+++ b/scripts/makefile.dec
@@ -5,7 +5,7 @@
 
 # Library name:
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 LIBNAME = libpng14
 
diff --git a/scripts/makefile.elf b/scripts/makefile.elf
index b43b1e9..4059e1b 100644
--- a/scripts/makefile.elf
+++ b/scripts/makefile.elf
@@ -12,7 +12,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.gcmmx b/scripts/makefile.gcmmx
index 4917ffd..2e5edee 100644
--- a/scripts/makefile.gcmmx
+++ b/scripts/makefile.gcmmx
@@ -16,7 +16,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hp64 b/scripts/makefile.hp64
index 4add23d..a3f3648 100644
--- a/scripts/makefile.hp64
+++ b/scripts/makefile.hp64
@@ -18,7 +18,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hpgcc b/scripts/makefile.hpgcc
index 67ae91a..8da44d2 100644
--- a/scripts/makefile.hpgcc
+++ b/scripts/makefile.hpgcc
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hpux b/scripts/makefile.hpux
index 8a49a6f..3a66c77 100644
--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -18,7 +18,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.linux b/scripts/makefile.linux
index b5ff13e..5f5c7f7 100644
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.mingw b/scripts/makefile.mingw
index 29d9ca2..d66276f 100644
--- a/scripts/makefile.mingw
+++ b/scripts/makefile.mingw
@@ -81,7 +81,7 @@
 LIBNAME = libpng14
 PNGMAJ = 14 
 MINGDLL = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=libpng$(MINGDLL).dll
diff --git a/scripts/makefile.ne12bsd b/scripts/makefile.ne12bsd
index e8fa81d..a50badb 100644
--- a/scripts/makefile.ne12bsd
+++ b/scripts/makefile.ne12bsd
@@ -14,7 +14,7 @@
 
 LIB=	png14
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.4.0beta51
+SHLIB_MINOR=	1.4.0beta52
 SRCS=	pnggccrd.c png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 		pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 		pngwtran.c pngmem.c pngerror.c pngpread.c
diff --git a/scripts/makefile.netbsd b/scripts/makefile.netbsd
index 1e0b07f..2f15f5d 100644
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -13,7 +13,7 @@
 
 LIB=	png
 SHLIB_MAJOR=	3
-SHLIB_MINOR=	1.4.0beta51
+SHLIB_MINOR=	1.4.0beta52
 SRCS=	pnggccrd.c png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 		pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 		pngwtran.c pngmem.c pngerror.c pngpread.c
diff --git a/scripts/makefile.nommx b/scripts/makefile.nommx
index b654fdd..0decaf0 100644
--- a/scripts/makefile.nommx
+++ b/scripts/makefile.nommx
@@ -16,7 +16,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.openbsd b/scripts/makefile.openbsd
index 7d6446f..6d0f490 100644
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -8,7 +8,7 @@
 MANDIR= ${PREFIX}/man/cat
 
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.4.0beta51
+SHLIB_MINOR=	1.4.0beta52
 
 LIB=	png
 SRCS=	png.c pngerror.c pnggccrd.c pngget.c pngmem.c pngpread.c \
diff --git a/scripts/makefile.sco b/scripts/makefile.sco
index 04e478d..45653fb 100644
--- a/scripts/makefile.sco
+++ b/scripts/makefile.sco
@@ -9,7 +9,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.sggcc b/scripts/makefile.sggcc
index 4c17c7d..f0129ff 100644
--- a/scripts/makefile.sggcc
+++ b/scripts/makefile.sggcc
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME=libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.sgi b/scripts/makefile.sgi
index 4734325..1754073 100644
--- a/scripts/makefile.sgi
+++ b/scripts/makefile.sgi
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME=libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.so9 b/scripts/makefile.so9
index 62b9584..6ca4290 100644
--- a/scripts/makefile.so9
+++ b/scripts/makefile.so9
@@ -8,7 +8,7 @@
 
 # Library name:
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 LIBNAME = libpng14
 
diff --git a/scripts/makefile.solaris b/scripts/makefile.solaris
index 9734eb7..8e1d01b 100644
--- a/scripts/makefile.solaris
+++ b/scripts/makefile.solaris
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng14
 PNGMAJ = 14
-PNGMIN = 1.4.0beta51
+PNGMIN = 1.4.0beta52
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/pngos2.def b/scripts/pngos2.def
index bdc2e40..bf48236 100644
--- a/scripts/pngos2.def
+++ b/scripts/pngos2.def
@@ -2,7 +2,7 @@
 ; PNG.LIB module definition file for OS/2
 ;----------------------------------------
 
-; Version 1.4.0beta51
+; Version 1.4.0beta52
 
 LIBRARY		PNG
 DESCRIPTION	"PNG image compression library for OS/2"
diff --git a/scripts/pngwin.def b/scripts/pngwin.def
index 953a68a..ddd430a 100644
--- a/scripts/pngwin.def
+++ b/scripts/pngwin.def
@@ -5,7 +5,7 @@
 LIBRARY
 
 EXPORTS
-;Version 1.4.0beta51
+;Version 1.4.0beta52
   png_build_grayscale_palette
   png_chunk_error
   png_chunk_warning