if ($_GET["thumbnail"]!="") {
                           ...
                           ...
                           ...
		if ($cacheThumbnails) {
			imagejpeg($thumb, $thumbFile);
			chmod($thumbFile, "0777");
			readfile($thumbFile);
		} else {
			imagejpeg($thumb);
		}
	}
	die();
}
if ($_GET["download"]!="") {
                           ...
                           ...
                           ...	
		readfile($filename);
		die();
	}
}