diff --git a/scripts/pnglibconf.dfa b/scripts/pnglibconf.dfa
index c95b10255..e096c3ec4 100755
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -826,6 +826,9 @@ option GET_PALETTE_MAX enables READ_GET_PALETTE_MAX WRITE_GET_PALETTE_MAX
 option READ_GET_PALETTE_MAX requires READ_CHECK_FOR_INVALID_INDEX disabled
 option WRITE_GET_PALETTE_MAX requires WRITE_CHECK_FOR_INVALID_INDEX disabled
 
+# added at libpng-1.6.3
+option READ_OPTIMIZE_WINDOWBITS requires READ
+
 # Simplified API options (added at libpng-1.6.0)
 # Read:
 option SIMPLIFIED_READ,
diff --git a/scripts/pnglibconf.h.prebuilt b/scripts/pnglibconf.h.prebuilt
index 18b0323de..4394c0097 100644
--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -2,7 +2,7 @@
 
 /* pnglibconf.h - library build configuration */
 
-/* Libpng version 1.6.3beta04 - April 30, 2013 */
+/* Libpng version 1.6.3beta04 - May 6, 2013 */
 
 /* Copyright (c) 1998-2013 Glenn Randers-Pehrson */
 
@@ -108,6 +108,7 @@
 /*#undef PNG_SET_OPTION_SUPPORTED*/
 #define PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
 #define PNG_SET_USER_LIMITS_SUPPORTED
+#define PNG_READ_OPTIMIZE_WINDOWBITS_SUPPORTED
 #define PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
 #define PNG_SIMPLIFIED_READ_BGR_SUPPORTED
 #define PNG_SIMPLIFIED_READ_SUPPORTED