Minor optimization.
diff --git a/MagickCore/image.c b/MagickCore/image.c
index b8cae9c..1f6d36c 100644
--- a/MagickCore/image.c
+++ b/MagickCore/image.c
@@ -1448,9 +1448,9 @@
   if (mask_image == (Image *) NULL)
     return((Image *) NULL);
   status=MagickTrue;
-  (void) SetImageColorspace(mask_image,GRAYColorspace,exception);
   mask_image->read_mask=MagickFalse;
   mask_image->alpha_trait=UndefinedPixelTrait;
+  (void) SetImageColorspace(mask_image,GRAYColorspace,exception);
   image_view=AcquireVirtualCacheView(image,exception);
   mask_view=AcquireAuthenticCacheView(mask_image,exception);
   for (y=0; y < (ssize_t) image->rows; y++)