make the parser spit out filenames of images it cant load

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24875 a1c6a512-1295-4272-9138-f99709370657

apps/gui/skin_engine/skin_parser.c

@@ -2014,6 +2014,7 @@ static bool load_skin_bmp(struct wps_data *wps_data, struct bitmap *bitmap, char
     else
     {
         /* Abort if we can't load an image */
+        DEBUGF("Couldn't load '%s'\n", img_path);
         return false;
     }
 }