https://github.com/ImageMagick/ImageMagick/issues/281

diff --git a/MagickCore/attribute.c b/MagickCore/attribute.c
index d9f088ad7584590b7c7b8c1eedec073f2983616f..f6510b7bf318451a4a2326632aead2a9c53f7747 100644 (file)
--- a/MagickCore/attribute.c
+++ b/MagickCore/attribute.c
@@ -1264,7 +1264,7 @@ MagickExport MagickBooleanType SetImageType(Image *image,const ImageType type,
           status=QuantizeImage(quantize_info,image,exception);
           quantize_info=DestroyQuantizeInfo(quantize_info);
         }
-      image->colors=2;
+      status=AcquireImageColormap(image,2,exception);
       image->alpha_trait=UndefinedPixelTrait;
       break;
     }