Codice PHP:
$src = imagecreatefromjpeg($_SERVER['DOCUMENT_ROOT'].'/image.jpg');
$logo = imagecreatefrompng($_SERVER['DOCUMENT_ROOT'].'/logo.png');
imagecopy($src, $logo, 10, 10, 0, 0, imagesx($logo), imagesy($logo));
imagedestroy($logo);
header("Content-type: image/jpeg");
imagejpeg($src);