1 files changed, 1 insertions, 1 deletions

diff --git a/src/image.c b/src/image.c
index dfa8941ab3c..cf96cae0385 100644
--- a/src/image.c
+++ b/src/image.c
@@ -3690,7 +3690,7 @@ xpm_load (struct frame *f, struct image *img)
       int i;
       uint32_t *od = (uint32_t *)data;
       uint32_t *id = (uint32_t *)img->ximg->data;
-      unsigned char *mid = img->mask_img ? img->mask_img->data : 0;
+      char *mid = img->mask_img ? img->mask_img->data : 0;
       uint32_t bgcolor = get_spec_bg_or_alpha_as_argb (img, f);
 
       for (i = 0; i < height; ++i)