/* pass through extension records */
if (DGifGetExtension(GifFileIn, &ExtCode, &Extension) == GIF_ERROR)
QuitGifError(GifFileIn, GifFileOut);
+ if (Extension == NULL)
+ break;
if (EGifPutExtensionLeader(GifFileOut, ExtCode) == GIF_ERROR)
QuitGifError(GifFileIn, GifFileOut);
if (EGifPutExtensionBlock(GifFileOut,