diff --git a/ANNOUNCE b/ANNOUNCE
index bc38faf13..e78709093 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -48,7 +48,8 @@ Version 1.5.10beta02 [February 27, 2012]
 Version 1.5.10beta03 [March 6, 2012]
   Removed unused "current_text" members of png_struct and the png_free()
     of png_ptr->current_text from pngread.c
-  Added palette-index checking.
+  Added palette-index checking. Issue a png_warning() if an invalid index is
+    found.
 
 Version 1.5.10beta04 [March 10, 2012]
   Fixed PNG_LIBPNG_BUILD_BASE_TYPE definition.
@@ -57,6 +58,7 @@ Version 1.5.10beta04 [March 10, 2012]
 
 Version 1.5.10beta05 [March 10, 2012]
   Reject all iCCP chunks after the first, even if the first one is invalid.
+  Issue a png_benign_error() instead of png_warning() about bad palette index.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index 78857d80b..f59777bd4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3833,7 +3833,8 @@ Version 1.5.10beta02 [February 27, 2012]
 Version 1.5.10beta03 [March 6, 2012]
   Removed unused "current_text" members of png_struct and the png_free()
     of png_ptr->current_text from pngread.c
-  Added palette-index checking.
+  Added palette-index checking. Issue a png_warning() if an invalid index is
+    found.
 
 Version 1.5.10beta04 [March 10, 2012]
   Fixed PNG_LIBPNG_BUILD_BASE_TYPE definition.
@@ -3842,6 +3843,7 @@ Version 1.5.10beta04 [March 10, 2012]
 
 Version 1.5.10beta05 [March 10, 2012]
   Reject all iCCP chunks after the first, even if the first one is invalid.
+  Issue a png_benign_error() instead of png_warning() about bad palette index.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/libpng-manual.txt b/libpng-manual.txt
index 7fcfd1697..865f96fa8 100644
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -4143,7 +4143,8 @@ From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
 function) incorrectly returned a value of type png_uint_32.
 
 Checking for invalid palette index on read or write was added at libpng
-1.5.10.  This is enabled by default but can be disabled in each png_ptr with
+1.5.10.  When an invalid index is found, libpng issues a benign error.
+This is enabled by default but can be disabled in each png_ptr with
 
    png_set_check_for_invalid_index(png_ptr, allowed);
 
diff --git a/libpng.3 b/libpng.3
index b6aaa919f..ac3f15f23 100644
--- a/libpng.3
+++ b/libpng.3
@@ -5125,7 +5125,8 @@ From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
 function) incorrectly returned a value of type png_uint_32.
 
 Checking for invalid palette index on read or write was added at libpng
-1.5.10.  This is enabled by default but can be disabled in each png_ptr with
+1.5.10.  When an invalid index is found, libpng issues a benign error.
+This is enabled by default but can be disabled in each png_ptr with
 
    png_set_check_for_invalid_index(png_ptr, allowed);
 
diff --git a/pngread.c b/pngread.c
index 6f949f630..3e487dea0 100644
--- a/pngread.c
+++ b/pngread.c
@@ -805,7 +805,7 @@ png_read_end(png_structp png_ptr, png_infop info_ptr)
    /* Report invalid palette index; added at libng-1.5.10 */
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
       png_ptr->num_palette_max > png_ptr->num_palette)
-     png_warning(png_ptr, "Read palette index exceeding num_palette");
+     png_benign_error(png_ptr, "Read palette index exceeding num_palette");
 #endif
 
    do
diff --git a/pngwrite.c b/pngwrite.c
index 74aa7368e..87550d6b3 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -307,7 +307,7 @@ png_write_end(png_structp png_ptr, png_infop info_ptr)
 
 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
    if (png_ptr->num_palette_max > png_ptr->num_palette)
-      png_warning(png_ptr, "Wrote palette index exceeding num_palette");
+      png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
 #endif
 
    /* See if user wants us to write information chunks */