Convert an image to faux sepia tone.

sepia.php

<?php

@$data = file_get_contents($_GET['image']);
if (!$data) {
    header("HTTP/1.1 400 Bad Request");
    exit;
}
@$img = imagecreatefromstring($data);
if (!$img) {
    header("HTTP/1.1 400 Bad Request");
    exit;
}

function output_handler($output) {
    $expires = 60*60*24*30;
    header('Expires: ' . gmdate("D, d M Y H:i:s", time() + $expires) . ' GMT');
    header('Cache-control: public, max-age=' . $expires);
    header('Content-type: image/png');
    header('Content-Length: ' . strlen($output));
    return $output;
}


imagefilter($img, IMG_FILTER_GRAYSCALE);
imagefilter($img, IMG_FILTER_COLORIZE, 90, 60, 40); 

ob_start("output_handler");
imagepng($img);
ob_end_flush();