https://github.com/ImageMagick/ImageMagick/issues/786

diff --git a/coders/icon.c b/coders/icon.c
index 3de0ad3b8a9f272f870e29e547982b781652a499..0cd79140b38e57386fb124090481567991946711 100644 (file)
--- a/coders/icon.c
+++ b/coders/icon.c
@@ -991,7 +991,8 @@ static MagickBooleanType WriteICONImage(const ImageInfo *image_info,
             return(MagickFalse);
           }
         write_info=CloneImageInfo(image_info);
-        (void) CopyMagickString(write_info->filename,"PNG:",MagickPathExtent);
+        (void) CopyMagickString(write_info->magick,"PNG",MagickPathExtent);
+        length=0;
 
         /* Don't write any ancillary chunks except for gAMA */
         (void) SetImageArtifact(write_image,"png:include-chunk","none,gama");