diff --git a/wand/magick-image.c b/wand/magick-image.c
index ccb5451b6f..4d313f1192 100644
--- a/wand/magick-image.c
+++ b/wand/magick-image.c
@@ -10575,6 +10575,7 @@ WandExport MagickBooleanType MagickSetImageFormat(MagickWand *wand,
     return(MagickFalse);
   ClearMagickException(wand->exception);
   (void) CopyMagickString(wand->images->magick,format,MaxTextExtent);
+  LocaleUpper(wand->images->magick);
   return(MagickTrue);
 }