diff --git a/ANNOUNCE b/ANNOUNCE
index bd7367d1..0aaedc77 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.2.15rc4 - December 27, 2006
+Libpng 1.2.15rc5 - December 29, 2006
 
 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.
@@ -9,32 +9,32 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script
 
-   libpng-1.2.15rc4.tar.gz
-   libpng-1.2.15rc4.tar.bz2
+   libpng-1.2.15rc5.tar.gz
+   libpng-1.2.15rc5.tar.bz2
 
 Source files with LF line endings (for Unix/Linux) without the
 "configure" script
 
-   libpng-1.2.15rc4-no-config.tar.gz
-   libpng-1.2.15rc4-no-config.tar.bz2
+   libpng-1.2.15rc5-no-config.tar.gz
+   libpng-1.2.15rc5-no-config.tar.bz2
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   lp1215r04.zip
-   lp1215r04.tar.bz2
+   lp1215r05.zip
+   lp1215r05.tar.bz2
 
 Project files
 
-   libpng-1.2.15rc4-project-netware.zip
-   libpng-1.2.15rc4-project-wince.zip
+   libpng-1.2.15rc5-project-netware.zip
+   libpng-1.2.15rc5-project-wince.zip
 
 Other information:
 
-   libpng-1.2.15rc4-README.txt
-   libpng-1.2.15rc4-KNOWNBUGS.txt
-   libpng-1.2.15rc4-LICENSE.txt
-   libpng-1.2.15rc4-Y2K-compliance.txt
+   libpng-1.2.15rc5-README.txt
+   libpng-1.2.15rc5-KNOWNBUGS.txt
+   libpng-1.2.15rc5-LICENSE.txt
+   libpng-1.2.15rc5-Y2K-compliance.txt
 
 Changes since the last public release (1.2.14):
 
@@ -72,6 +72,9 @@ version 1.2.15rc3 [December 25, 2006]
 version 1.2.15rc4 [December 27, 2006]
   Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set.
 
+version 1.2.15rc5 [December 29, 2006]
+  Revised handling of rgb_to_gray.
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 
 (subscription required; visit 
diff --git a/CHANGES b/CHANGES
index 60522c89..7fd7a784 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1674,6 +1674,9 @@ version 1.2.15rc3 [December 25, 2006]
 version 1.2.15rc4 [December 27, 2006]
   Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set.
 
+version 1.2.15rc5 [December 29, 2006]
+  Revised handling of rgb_to_gray.
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
diff --git a/INSTALL b/INSTALL
index b3a0e3b6..535b1d8b 100644
--- a/INSTALL
+++ b/INSTALL
@@ -1,5 +1,5 @@
 
-Installing libpng version 1.2.15rc4 - December 27, 2006
+Installing libpng version 1.2.15rc5 - December 29, 2006
 
 On Unix/Linux and similar systems, you can simply type
 
@@ -44,7 +44,7 @@ to have access to the zlib.h and zconf.h include files that
 correspond to the version of zlib that's installed.
 
 You can rename the directories that you downloaded (they
-might be called "libpng-1.2.15rc4" or "lpng109" and "zlib-1.2.1"
+might be called "libpng-1.2.15rc5" 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:
@@ -101,14 +101,14 @@ include
  CMakeLists.txt    =>  "cmake" script
  makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
  makefile.elf      =>  Linux/ELF makefile symbol versioning,
-                       gcc, creates libpng12.so.0.1.2.15rc4)
+                       gcc, creates libpng12.so.0.1.2.15rc5)
  makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng12.so.0.1.2.15rc4)
+                       (gcc, creates libpng12.so.0.1.2.15rc5)
  makefile.gcmmx    =>  Linux/ELF makefile
-                       (gcc, creates libpng12.so.0.1.2.15rc4,
+                       (gcc, creates libpng12.so.0.1.2.15rc5,
                        uses assembler code tuned for Intel MMX platform)
  makefile.nommx    =>  Linux/ELF makefile
-                       (gcc, creates libpng12.so.0.1.2.15rc4
+                       (gcc, creates libpng12.so.0.1.2.15rc5
                        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
@@ -131,12 +131,12 @@ include
  makefile.openbsd  =>  OpenBSD makefile
  makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
  makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng12.so.0.1.2.15rc4)
+                       creates libpng12.so.0.1.2.15rc5)
  makefile.sunos    =>  Sun makefile
  makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng12.so.0.1.2.15rc4)
+                       creates libpng12.so.0.1.2.15rc5)
  makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng12.so.0.1.2.15rc4)
+                       creates libpng12.so.0.1.2.15rc5)
  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 5cbc53b2..2e2cb1dd 100644
--- a/KNOWNBUG
+++ b/KNOWNBUG
@@ -1,5 +1,5 @@
 
-Known bugs in libpng version 1.2.15rc4
+Known bugs in libpng version 1.2.15rc5
 
 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 b38dcec1..b461c160 100644
--- a/LICENSE
+++ b/LICENSE
@@ -8,7 +8,7 @@ COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.2.6, August 15, 2004, through 1.2.15rc4, December 27, 2006, are
+libpng versions 1.2.6, August 15, 2004, through 1.2.15rc5, December 29, 2006, are
 Copyright (c) 2004, 2006 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 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-December 27, 2006
+December 29, 2006
diff --git a/README b/README
index 26a7bc83..61991387 100644
--- a/README
+++ b/README
@@ -1,4 +1,4 @@
-README for libpng version 1.2.15rc4 - December 27, 2006 (shared library 12.0)
+README for libpng version 1.2.15rc5 - December 29, 2006 (shared library 12.0)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.
@@ -190,11 +190,11 @@ Files in this distribution:
        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 libpng12.so.0.1.2.15rc4)
+                            gcc, creates libpng12.so.0.1.2.15rc5)
        makefile.linux   =>  Linux/ELF makefile
-                            (gcc, creates libpng12.so.0.1.2.15rc4)
+                            (gcc, creates libpng12.so.0.1.2.15rc5)
        makefile.gcmmx   =>  Linux/ELF makefile
-                            (gcc, creates libpng12.so.0.1.2.15rc4,
+                            (gcc, creates libpng12.so.0.1.2.15rc5,
                             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
@@ -216,12 +216,12 @@ Files in this distribution:
        makefile.openbsd =>  OpenBSD makefile
        makefile.sgi     =>  Silicon Graphics IRIX (cc, creates static lib)
        makefile.sggcc   =>  Silicon Graphics
-                            (gcc, creates libpng12.so.0.1.2.15rc4)
+                            (gcc, creates libpng12.so.0.1.2.15rc5)
        makefile.sunos   =>  Sun makefile
        makefile.solaris =>  Solaris 2.X makefile
-                            (gcc, creates libpng12.so.0.1.2.15rc4)
+                            (gcc, creates libpng12.so.0.1.2.15rc5)
        makefile.so9     =>  Solaris 9 makefile
-                            (gcc, creates libpng12.so.0.1.2.15rc4)
+                            (gcc, creates libpng12.so.0.1.2.15rc5)
        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/Y2KINFO b/Y2KINFO
index 3d805e90..d3636b92 100644
--- a/Y2KINFO
+++ b/Y2KINFO
@@ -1,13 +1,13 @@
    Y2K compliance in libpng:
    =========================
 
-      December 27, 2006
+      December 29, 2006
 
       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 1.2.15rc4 are Y2K compliant.  It is my belief that earlier
+      upward through 1.2.15rc5 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
diff --git a/configure b/configure
index 01f4057a..80693cb3 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.61 for libpng 1.2.15rc4.
+# Generated by GNU Autoconf 2.61 for libpng 1.2.15rc5.
 #
 # Report bugs to <png-mng-implement@lists.sourceforge.net>.
 #
@@ -728,8 +728,8 @@ SHELL=${CONFIG_SHELL-/bin/sh}
 # Identity of this package.
 PACKAGE_NAME='libpng'
 PACKAGE_TARNAME='libpng'
-PACKAGE_VERSION='1.2.15rc4'
-PACKAGE_STRING='libpng 1.2.15rc4'
+PACKAGE_VERSION='1.2.15rc5'
+PACKAGE_STRING='libpng 1.2.15rc5'
 PACKAGE_BUGREPORT='png-mng-implement@lists.sourceforge.net'
 
 ac_unique_file="pngget.c"
@@ -1405,7 +1405,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures libpng 1.2.15rc4 to adapt to many kinds of systems.
+\`configure' configures libpng 1.2.15rc5 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1475,7 +1475,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of libpng 1.2.15rc4:";;
+     short | recursive ) echo "Configuration of libpng 1.2.15rc5:";;
    esac
   cat <<\_ACEOF
 
@@ -1585,7 +1585,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-libpng configure 1.2.15rc4
+libpng configure 1.2.15rc5
 generated by GNU Autoconf 2.61
 
 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
@@ -1599,7 +1599,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by libpng $as_me 1.2.15rc4, which was
+It was created by libpng $as_me 1.2.15rc5, which was
 generated by GNU Autoconf 2.61.  Invocation command line was
 
   $ $0 $@
@@ -2269,7 +2269,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='libpng'
- VERSION='1.2.15rc4'
+ VERSION='1.2.15rc5'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -2440,7 +2440,7 @@ fi
 
 
 
-PNGLIB_VERSION=1.2.15rc4
+PNGLIB_VERSION=1.2.15rc5
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=2
 PNGLIB_RELEASE=15
@@ -21119,7 +21119,7 @@ exec 6>&1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by libpng $as_me 1.2.15rc4, which was
+This file was extended by libpng $as_me 1.2.15rc5, which was
 generated by GNU Autoconf 2.61.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -21172,7 +21172,7 @@ Report bugs to <bug-autoconf@gnu.org>."
 _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF
 ac_cs_version="\\
-libpng config.status 1.2.15rc4
+libpng config.status 1.2.15rc5
 configured by $0, generated by GNU Autoconf 2.61,
   with options \\"`echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`\\"
 
diff --git a/configure.ac b/configure.ac
index cb5173c1..953e711d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -18,12 +18,12 @@ AC_PREREQ(2.59)
 
 dnl Version number stuff here:
 
-AC_INIT([libpng], [1.2.15rc4], [png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng], [1.2.15rc5], [png-mng-implement@lists.sourceforge.net])
 AM_INIT_AUTOMAKE
 dnl stop configure from automagically running automake
 AM_MAINTAINER_MODE
 
-PNGLIB_VERSION=1.2.15rc4
+PNGLIB_VERSION=1.2.15rc5
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=2
 PNGLIB_RELEASE=15
diff --git a/libpng.3 b/libpng.3
index 43534e5d..2757d2be 100644
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "December 27, 2006"
+.TH LIBPNG 3 "December 29, 2006"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.2.15rc4
+libpng \- Portable Network Graphics (PNG) Reference Library 1.2.15rc5
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -410,7 +410,7 @@ Following is a copy of the libpng.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.2.15rc4 - December 27, 2006
+ libpng version 1.2.15rc5 - December 29, 2006
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2005 Glenn Randers-Pehrson
@@ -3327,13 +3327,13 @@ application:
 
 .SH IX. Y2K Compliance in libpng
 
-December 27, 2006
+December 29, 2006
 
 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 1.2.15rc4 are Y2K compliant.  It is my belief that earlier
+upward through 1.2.15rc5 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
@@ -3507,8 +3507,8 @@ the first widely used release:
  1.0.22rc1           10    10022  10.so.0.22[.0]
  1.2.14rc1           13    10214  12.so.0.14[.0]
  1.2.15beta1-6       13    10215  12.so.0.15[.0]
- 1.0.23rc1-4         10    10023  10.so.0.23[.0]
- 1.2.15rc1-4         13    10215  12.so.0.15[.0]
+ 1.0.23rc1-5         10    10023  10.so.0.23[.0]
+ 1.2.15rc1-5         13    10215  12.so.0.15[.0]
 
 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -3564,7 +3564,7 @@ possible without all of you.
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
 
-Libpng version 1.2.15rc4 - December 27, 2006:
+Libpng version 1.2.15rc5 - December 29, 2006:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
 
@@ -3585,7 +3585,7 @@ included in the libpng distribution, the latter shall prevail.)
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.2.6, August 15, 2004, through 1.2.15rc4, December 27, 2006, are
+libpng versions 1.2.6, August 15, 2004, through 1.2.15rc5, December 29, 2006, are
 Copyright (c) 2004-2006 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
@@ -3684,7 +3684,7 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-December 27, 2006
+December 29, 2006
 
 .\" end of man page
 
diff --git a/libpng.txt b/libpng.txt
index cb71b2e7..1a2323b6 100644
--- a/libpng.txt
+++ b/libpng.txt
@@ -1,6 +1,6 @@
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.2.15rc4 - December 27, 2006
+ libpng version 1.2.15rc5 - December 29, 2006
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2005 Glenn Randers-Pehrson
@@ -2917,13 +2917,13 @@ application:
 
 IX. Y2K Compliance in libpng
 
-December 27, 2006
+December 29, 2006
 
 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 1.2.15rc4 are Y2K compliant.  It is my belief that earlier
+upward through 1.2.15rc5 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/libpngpf.3 b/libpngpf.3
index d440d501..12f888d3 100644
--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "December 27, 2006"
+.TH LIBPNGPF 3 "December 29, 2006"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.2.15rc4
+libpng \- Portable Network Graphics (PNG) Reference Library 1.2.15rc5
 (private functions)
 .SH SYNOPSIS
 \fB#include <png.h>\fP
diff --git a/png.5 b/png.5
index c95683c9..141d7cca 100644
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "December 27, 2006"
+.TH PNG 5 "December 29, 2006"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
diff --git a/png.c b/png.c
index f9fc8341..51343767 100644
--- a/png.c
+++ b/png.c
@@ -13,7 +13,7 @@
 #include "png.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_2_15rc4 Your_png_h_is_not_version_1_2_15rc4;
+typedef version_1_2_15rc5 Your_png_h_is_not_version_1_2_15rc5;
 
 /* Version information for C files.  This had better match the version
  * string defined in png.h.  */
@@ -701,7 +701,7 @@ png_charp PNGAPI
 png_get_copyright(png_structp png_ptr)
 {
    if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
-   return ((png_charp) "\n libpng version 1.2.15rc4 - December 27, 2006\n\
+   return ((png_charp) "\n libpng version 1.2.15rc5 - December 29, 2006\n\
    Copyright (c) 1998-2006 Glenn Randers-Pehrson\n\
    Copyright (c) 1996-1997 Andreas Dilger\n\
    Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
diff --git a/png.h b/png.h
index 59606d86..d2036cb9 100644
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.2.15rc4 - December 27, 2006
+ * libpng version 1.2.15rc5 - December 29, 2006
  * Copyright (c) 1998-2006 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 1.2.15rc4 - December 27, 2006: Glenn
+ *  libpng versions 0.97, January 1998, through 1.2.15rc5 - December 29, 2006: Glenn
  *  See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -135,8 +135,8 @@
  *    1.0.22                  10    10022  10.so.0.22[.0]
  *    1.2.14                  13    10214  12.so.0.14[.0]
  *    1.2.15beta1-6           13    10215  12.so.0.15[.0]
- *    1.0.23rc1-4             10    10023  10.so.0.23[.0]
- *    1.2.15rc1-4             13    10215  12.so.0.15[.0]
+ *    1.0.23rc1-5             10    10023  10.so.0.23[.0]
+ *    1.2.15rc1-5             13    10215  12.so.0.15[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
@@ -166,7 +166,7 @@
  * If you modify libpng you may insert additional notices immediately following
  * this sentence.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.2.15rc4, December 27, 2006, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.2.15rc5, December 29, 2006, are
  * Copyright (c) 2004, 2006 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:
@@ -278,13 +278,13 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    December 27, 2006
+ *    December 29, 2006
  *
  *    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 1.2.15rc4 are Y2K compliant.  It is my belief that earlier
+ *    upward through 1.2.15rc5 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
@@ -340,9 +340,9 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.2.15rc4"
+#define PNG_LIBPNG_VER_STRING "1.2.15rc5"
 #define PNG_HEADER_VERSION_STRING \
-   " libpng version 1.2.15rc4 - December 27, 2006 (header)\n"
+   " libpng version 1.2.15rc5 - December 29, 2006 (header)\n"
 
 #define PNG_LIBPNG_VER_SONUM   0
 #define PNG_LIBPNG_VER_DLLNUM  13
@@ -354,7 +354,7 @@
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero: */
 
-#define PNG_LIBPNG_VER_BUILD  4
+#define PNG_LIBPNG_VER_BUILD  5
 
 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -1388,7 +1388,7 @@ struct png_struct_def
 /* 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_2_15rc4;
+typedef png_structp version_1_2_15rc5;
 
 typedef png_struct FAR * FAR * png_structpp;
 
diff --git a/pngconf.h b/pngconf.h
index d0c418e3..b82aa6b9 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.2.15rc4 - December 27, 2006
+ * libpng version 1.2.15rc5 - December 29, 2006
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2005 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngrtran.c b/pngrtran.c
index b8d1d921..3bf9f105 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -94,23 +94,6 @@ png_set_background(png_structp png_ptr,
    png_ptr->background_gamma = (float)background_gamma;
    png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
    png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);
-
-   /* Note:  if need_expand is set and color_type is either RGB or RGB_ALPHA
-    * (in which case need_expand is superfluous anyway), the background color
-    * might actually be gray yet not be flagged as such. This is not a problem
-    * for the current code, which uses PNG_BACKGROUND_IS_GRAY only to
-    * decide when to do the png_do_gray_to_rgb() transformation.
-    */
-   if ((need_expand && !(png_ptr->color_type & PNG_COLOR_MASK_COLOR)))
-   {
-      png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
-   } else if (!need_expand &&
-              background_color->red == background_color->green &&
-              background_color->red == background_color->blue)
-   {
-      png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
-      png_ptr->background.gray = background_color->red;
-   }
 }
 #endif
 
@@ -738,6 +721,32 @@ png_init_read_transformations(png_structp png_ptr)
 #endif
 
 #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+   /* Detect gray background and attempt to enable optimization
+    * for gray --> RGB case */
+   /* Note:  if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+    * RGB_ALPHA (in which case need_expand is superfluous anyway), the
+    * background color might actually be gray yet not be flagged as such.
+    * This is not a problem for the current code, which uses
+    * PNG_BACKGROUND_IS_GRAY only to decide when to do the
+    * png_do_gray_to_rgb() transformation.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+       !(color_type & PNG_COLOR_MASK_COLOR))
+   {
+          png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+   } else if ((png_ptr->transformations & PNG_BACKGROUND) &&
+              !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+              (png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+              png_ptr->background.red == png_ptr->background.green &&
+              png_ptr->background.red == png_ptr->background.blue)
+   {
+          png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+          png_ptr->background.gray = png_ptr->background.red;
+   }
+#endif
+
    if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
        (png_ptr->transformations & PNG_EXPAND))
    {
diff --git a/pngtest.c b/pngtest.c
index 6906c45e..8cd605d9 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -1547,4 +1547,4 @@ main(int argc, char *argv[])
 }
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_2_15rc4 your_png_h_is_not_version_1_2_15rc4;
+typedef version_1_2_15rc5 your_png_h_is_not_version_1_2_15rc5;
diff --git a/scripts/libpng-config-head.in b/scripts/libpng-config-head.in
index 02710df5..db4a1e9b 100755
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -8,7 +8,7 @@
 
 # Modeled after libxml-config.
 
-version=1.2.15rc4
+version=1.2.15rc5
 prefix=""
 libdir=""
 libs=""
diff --git a/scripts/libpng.pc-configure.in b/scripts/libpng.pc-configure.in
index 26bd14a5..f1be9cd9 100644
--- a/scripts/libpng.pc-configure.in
+++ b/scripts/libpng.pc-configure.in
@@ -5,6 +5,6 @@ includedir=@includedir@/libpng12
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.2.15rc4
+Version: 1.2.15rc5
 Libs: -L${libdir} -lpng12
 Cflags: -I${includedir} @LIBPNG_NO_MMX@
diff --git a/scripts/libpng.pc.in b/scripts/libpng.pc.in
index 03fb3d48..f143a5ad 100644
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -5,6 +5,6 @@ includedir=@includedir@/libpng12
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.2.15rc4
+Version: 1.2.15rc5
 Libs: -L${libdir} -lpng12
 Cflags: -I${includedir}
diff --git a/scripts/makefile.32sunu b/scripts/makefile.32sunu
index 0ec5365d..408e7244 100644
--- a/scripts/makefile.32sunu
+++ b/scripts/makefile.32sunu
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.64sunu b/scripts/makefile.64sunu
index 0787d115..1e6f269e 100644
--- a/scripts/makefile.64sunu
+++ b/scripts/makefile.64sunu
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.aix b/scripts/makefile.aix
index df64f670..607d5160 100644
--- a/scripts/makefile.aix
+++ b/scripts/makefile.aix
@@ -20,7 +20,7 @@ LN_SF = ln -f -s
 
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 prefix=/usr/local
diff --git a/scripts/makefile.beos b/scripts/makefile.beos
index 595ebf0b..d45800e5 100644
--- a/scripts/makefile.beos
+++ b/scripts/makefile.beos
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.cygwin b/scripts/makefile.cygwin
index bf3f9cfb..742bc245 100644
--- a/scripts/makefile.cygwin
+++ b/scripts/makefile.cygwin
@@ -80,7 +80,7 @@ CFLAGS= $(strip $(MINGW_CCFLAGS) $(addprefix -I,$(ZLIBINC)) \
 LIBNAME = libpng12
 PNGMAJ = 0
 CYGDLL = 12
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=cygpng$(CYGDLL).dll
diff --git a/scripts/makefile.darwin b/scripts/makefile.darwin
index c27b8921..65224842 100644
--- a/scripts/makefile.darwin
+++ b/scripts/makefile.darwin
@@ -19,7 +19,7 @@ ZLIBINC=../zlib
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.dec b/scripts/makefile.dec
index c102bf00..5226df1d 100644
--- a/scripts/makefile.dec
+++ b/scripts/makefile.dec
@@ -5,7 +5,7 @@
 
 # Library name:
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 LIBNAME = libpng12
 
diff --git a/scripts/makefile.elf b/scripts/makefile.elf
index 968e61c5..2775b880 100644
--- a/scripts/makefile.elf
+++ b/scripts/makefile.elf
@@ -12,7 +12,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.gcmmx b/scripts/makefile.gcmmx
index 0a4c2576..f97b9568 100644
--- a/scripts/makefile.gcmmx
+++ b/scripts/makefile.gcmmx
@@ -16,7 +16,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hp64 b/scripts/makefile.hp64
index a6ca46d3..9653b58c 100644
--- a/scripts/makefile.hp64
+++ b/scripts/makefile.hp64
@@ -18,7 +18,7 @@ ZLIBINC=/opt/zlib/include
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hpgcc b/scripts/makefile.hpgcc
index 9592ebc5..dcdded01 100644
--- a/scripts/makefile.hpgcc
+++ b/scripts/makefile.hpgcc
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hpux b/scripts/makefile.hpux
index 019c53cf..a8878e14 100644
--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -18,7 +18,7 @@ ZLIBINC=/opt/zlib/include
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.linux b/scripts/makefile.linux
index 32695f3a..c11ffb16 100644
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.mingw b/scripts/makefile.mingw
index c4080eb2..c5ddccd6 100644
--- a/scripts/makefile.mingw
+++ b/scripts/makefile.mingw
@@ -76,7 +76,7 @@ CFLAGS= $(strip $(MINGW_CCFLAGS) $(addprefix -I,$(ZLIBINC)) \
 LIBNAME = libpng12
 PNGMAJ = 0
 MINGDLL = 12
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=libpng$(MINGDLL).dll
diff --git a/scripts/makefile.ne12bsd b/scripts/makefile.ne12bsd
index 0e08e291..7101e418 100644
--- a/scripts/makefile.ne12bsd
+++ b/scripts/makefile.ne12bsd
@@ -13,7 +13,7 @@ INCSDIR=${LOCALBASE}/include/libpng12
 
 LIB=	png12
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.2.15rc4
+SHLIB_MINOR=	1.2.15rc5
 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 b8d9c079..c2e80503 100644
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -13,7 +13,7 @@ INCSDIR=${LOCALBASE}/include/libpng
 
 LIB=	png
 SHLIB_MAJOR=	3
-SHLIB_MINOR=	1.2.15rc4
+SHLIB_MINOR=	1.2.15rc5
 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 d1ef7ca2..b7682c48 100644
--- a/scripts/makefile.nommx
+++ b/scripts/makefile.nommx
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.openbsd b/scripts/makefile.openbsd
index 68624f38..a88e8f2a 100644
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -7,7 +7,7 @@ LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat
 
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.2.15rc4
+SHLIB_MINOR=	1.2.15rc5
 
 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 5a8016c7..ca2e0490 100644
--- a/scripts/makefile.sco
+++ b/scripts/makefile.sco
@@ -9,7 +9,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.sggcc b/scripts/makefile.sggcc
index 96a661d6..58bea165 100644
--- a/scripts/makefile.sggcc
+++ b/scripts/makefile.sggcc
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.sgi b/scripts/makefile.sgi
index e40d3f0f..bf44f4b8 100644
--- a/scripts/makefile.sgi
+++ b/scripts/makefile.sgi
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.so9 b/scripts/makefile.so9
index e0bd142b..a546a330 100644
--- a/scripts/makefile.so9
+++ b/scripts/makefile.so9
@@ -8,7 +8,7 @@
 
 # Library name:
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 LIBNAME = libpng12
 
diff --git a/scripts/makefile.solaris b/scripts/makefile.solaris
index ac11b063..2ca810bf 100644
--- a/scripts/makefile.solaris
+++ b/scripts/makefile.solaris
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.15rc4
+PNGMIN = 1.2.15rc5
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/pngos2.def b/scripts/pngos2.def
index 7a78c181..885bf677 100644
--- a/scripts/pngos2.def
+++ b/scripts/pngos2.def
@@ -2,7 +2,7 @@
 ; PNG.LIB module definition file for OS/2
 ;----------------------------------------
 
-; Version 1.2.15rc4
+; Version 1.2.15rc5
 
 LIBRARY		PNG
 DESCRIPTION	"PNG image compression library for OS/2"
diff --git a/scripts/pngw32.def b/scripts/pngw32.def
index e57bed2f..60e1e85f 100644
--- a/scripts/pngw32.def
+++ b/scripts/pngw32.def
@@ -5,7 +5,7 @@
 LIBRARY
 
 EXPORTS
-;Version 1.2.15rc4
+;Version 1.2.15rc5
   png_build_grayscale_palette  @1
   png_check_sig        @2
   png_chunk_error      @3