header('Content-type: image/jpeg');
header('Content-type: image/gif');
$fileName = "sample.jpg";
header("Content-Type: application/force-download; name=$fileName");
header("Content-Transfer-Encoding: binary");
header("Content-Length: $size");
header("Content-Disposition: attachment; filename=$fileName");
header("Expires: 0");
header("Cache-Control: no-cache, must-revalidate");
header("Pragma: no-cache");
readFile("images/$fileName");