@@ -125,26 +125,21 @@ static int gif_read_image(GifState *s)

             case 1:

                 y1 += 8;

                 ptr += linesize * 8;

-                if (y1 >= height) {

-                    y1 = pass ? 2 : 4;

-                    ptr = ptr1 + linesize * y1;

-                    pass++;

-                }

                 break;

             case 2:

                 y1 += 4;

                 ptr += linesize * 4;

-                if (y1 >= height) {

-                    y1 = 1;

-                    ptr = ptr1 + linesize;

-                    pass++;

-                }

                 break;

             case 3:

                 y1 += 2;

                 ptr += linesize * 2;

                 break;

             }

+            while (y1 >= height) {

+                y1 = 4 >> pass;

+                ptr = ptr1 + linesize * y1;

+                pass++;

+            }

         } else {

             ptr += linesize;

         }