1 files changed, 1 insertions, 1 deletions

diff --git a/src/image.c b/src/image.c
index 31b3f01c17d..7d15a4725c5 100644
--- a/src/image.c
+++ b/src/image.c
@@ -7238,7 +7238,7 @@ gif_load (struct frame *f, struct image *img)
               /* From gif89a spec: 1 = "keep in place", 2 = "restore
                  to background".  Treat any other value like 2.  */
               disposal = (extblock->Bytes[0] >> 2) & 7;
-              transparency_color_index = extblock->Bytes[3];
+              transparency_color_index = (unsigned char) extblock->Bytes[3];
               break;
             }
         }