Soll ich??
<?php
header('content-type: image/jpeg');
$img = $_GET['img'];
$watermark = imagecreatefrompng('watermark.png');
$watermark_width = imagesx($watermark);
$watermark_height = imagesy($watermark);
$image = imagecreatetruecolor($watermark_width, $watermark_height);
$image = imagecreatefromjpeg("$img");
$size = getimagesize("$img");
$dest_x = $size[0] - $watermark_width - 5;
$dest_y = $size[1] - $watermark_height - 5;
imagecopymerge($image, $watermark, $dest_x, $dest_y, 0, 0, $watermark_width, $watermark_height, 100);
imagejpeg($image);
imagedestroy($image);
imagedestroy($watermark);
?>
watermark.png nach Belieben, ins Root,
jpg.html in: template/<dein-template>/media
<img src="./watermark.php?img={media_src}" border="1" alt="{image_name}"{width_height} /><br />