Make the png encoder treat incoming image depth as 8 if it is less than 8.

diff --git a/coders/png.c b/coders/png.c
index ac3ce4e3241f82bc26372b3f41f7f2fe732a504b..67f187df91cf3d04aa2ffe27c688ecda6b83dd42 100644 (file)
--- a/coders/png.c
+++ b/coders/png.c
@@ -7092,6 +7092,8 @@ static MagickBooleanType WriteOnePNGImage(MngInfo *mng_info,
     }
 #endif
 
+  if (image->depth < 8)
+     image->depth=8;
 
 #if (MAGICKCORE_QUANTUM_DEPTH > 16)
   /* PNG does not handle depths greater than 16 so reduce it even