diff -ru4NwbB libpng-1.4.12/configure.ac libpng-1.4.13beta02/configure.ac
--- libpng-1.4.12/configure.ac	2012-07-09 19:38:27.680297736 -0500
+++ libpng-1.4.13beta02/configure.ac	2013-01-03 14:05:28.276151825 -0600
@@ -30,9 +30,9 @@
 
 dnl End of version number stuff
 
 AC_CONFIG_SRCDIR([pngget.c])
-AM_CONFIG_HEADER(config.h)
+AC_CONFIG_HEADERS([config.h])
 
 # Checks for programs.
 AC_PROG_CC
 AC_PROG_LD
diff -ru4NwbB libpng-1.4.12/contrib/pngminim/encoder/README libpng-1.4.13beta02/contrib/pngminim/encoder/README
--- libpng-1.4.12/contrib/pngminim/encoder/README	2012-07-09 19:38:22.457063684 -0500
+++ libpng-1.4.13beta02/contrib/pngminim/encoder/README	2013-01-03 14:05:23.003751202 -0600
@@ -1,9 +1,10 @@
 This demonstrates the use of PNG_USER_CONFIG and pngusr.h
 
-To build a minimal write-only decoder with embedded libpng and zlib, run
+The makefile builds a minimal write-only encoder with embedded libpng
+and zlib.
 
-    gather.sh  # to collect needed files from pngminus, libpng, and zlib
-    make
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
  
 If you prefer to use the shared libraries, go to contrib/pngminus
 and build the pnm2png application there. 
diff -ru4NwbB libpng-1.4.12/png.h libpng-1.4.13beta02/png.h
--- libpng-1.4.12/png.h	2012-07-09 19:38:21.563699618 -0500
+++ libpng-1.4.13beta02/png.h	2013-01-03 14:05:22.154343079 -0600
@@ -169,8 +169,9 @@
  *    1.4.10                  14    10410  14.so.14.10[.0]
  *    1.4.11rc01              14    10411  14.so.14.11[.0]
  *    1.4.11                  14    10411  14.so.14.11[.0]
  *    1.4.12                  14    10412  14.so.14.12[.0]
+ *    1.4.13beta01-02         14    10413  14.so.14.13[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
  *    used for changes in backward compatibility, as it is intended.  The
diff -ru4NwbB libpng-1.4.12/pngconf.h libpng-1.4.13beta02/pngconf.h
--- libpng-1.4.12/pngconf.h	2012-07-09 19:38:21.573644597 -0500
+++ libpng-1.4.13beta02/pngconf.h	2013-01-03 14:05:22.164280419 -0600
@@ -1388,31 +1388,25 @@
 #    endif
 #    ifndef PNG_NORETURN
 #      define PNG_NORETURN   __attribute__((__noreturn__))
 #    endif
+#    if __GNUC__ >= 3
 #    ifndef PNG_ALLOCATED
 #      define PNG_ALLOCATED  __attribute__((__malloc__))
 #    endif
 #    ifndef PNG_DEPRECATED
 #      define PNG_DEPRECATED __attribute__((__deprecated__))
 #    endif
-
-    /* This specifically protects structure members that should only be
-     * accessed from within the library, therefore should be empty during
-     * a library build.
-     */
-#    ifndef PNG_DEPSTRUCT
-#      define PNG_DEPSTRUCT  __attribute__((__deprecated__))
-#    endif
 #    ifndef PNG_PRIVATE
 #      if 0 /* Doesn't work so we use deprecated instead*/
 #        define PNG_PRIVATE \
           __attribute__((warning("This function is not exported by libpng.")))
 #      else
 #        define PNG_PRIVATE \
           __attribute__((__deprecated__))
 #      endif
-#    endif /* PNG_PRIVATE */
+#      endif
+#    endif /*  __GNUC__ >= 3 */
 #  endif /* __GNUC__ */
 #endif /* PNG_PEDANTIC_WARNINGS */
 
 #ifndef PNG_DEPRECATED
diff -ru4NwbB libpng-1.4.12/pngset.c libpng-1.4.13beta02/pngset.c
--- libpng-1.4.12/pngset.c	2012-07-09 19:38:21.687333269 -0500
+++ libpng-1.4.13beta02/pngset.c	2013-01-03 14:05:22.277589544 -0600
@@ -1,9 +1,9 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * Last changed in libpng 1.4.11 [March 29, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
+ * Last changed in libpng 1.4.13 [January 3, 2013]
+ * Copyright (c) 1998-2013 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.)
  *
  * This code is released under the libpng license.
@@ -835,8 +835,14 @@
 
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
+   if (num_trans < 0 || num_trans > PNG_MAX_PALETTE_LENGTH)
+      {
+        png_warning(png_ptr, "Ignoring invalid num_trans value");
+        return;
+      }
+
    if (trans_alpha != NULL)
    {
        /* It may not actually be necessary to set png_ptr->trans_alpha here;
         * we do it for backward compatibility with the way the png_handle_tRNS