diff --git a/mozilla/modules/libimg/src/gif.c b/mozilla/modules/libimg/src/gif.c
index 22c6ca4749d..80d030e1320 100644
--- a/mozilla/modules/libimg/src/gif.c
+++ b/mozilla/modules/libimg/src/gif.c
@@ -706,7 +706,7 @@ gif_clear_screen(gif_struct *gs)
         int src_trans_pixel_index;
         uint8 *rowbuf = gs->rowbuf;
         NI_PixmapHeader *src_header = ic->src_header;
-        IL_IRGB *saved_src_trans_pixel;
+        IL_IRGB *saved_src_trans_pixel, *saved_img_trans_pixel;
 
         /* Catch images that fall outside the logical screen. */
         if ((erase_x_offset + erase_width) > gs->screen_width)
@@ -714,12 +714,15 @@ gif_clear_screen(gif_struct *gs)
 
         /* We have to temporarily pretend the image is transparent
            so we can clear using the context's background color. */
+        saved_img_trans_pixel = ic->image->header.transparent_pixel;
         saved_src_trans_pixel = src_header->transparent_pixel;
         src_header->transparent_pixel = NULL;
+        ic->image->header.transparent_pixel = NULL;
 
         /* Pick an index for the source image's temporary transparent pixel.
            The actual choice is immaterial since it will only be used for
            the clear screen operation. */
+
         src_trans_pixel_index = 0;
         if (!il_gif_init_transparency(ic, src_trans_pixel_index))
             return MK_OUT_OF_MEMORY;
@@ -739,6 +742,7 @@ gif_clear_screen(gif_struct *gs)
         /* Reset the source image's transparent pixel to its former state. */
         il_gif_destroy_transparency(ic);
         src_header->transparent_pixel = saved_src_trans_pixel;
+        ic->image->header.transparent_pixel = saved_img_trans_pixel;
     }
     return 0;
 }