[pcparts]

Try this for watermark images on all products it worked ok on my local computer.

In function.thumb_imp

Change line 527 to this

$overlay = imagecreatefromgif($params['overlay']);

Under

/* load the "overlay"-image */

Create a folder watermark in your root images directory.

In skin1/product_thumbnail.tpl

Change this

{thumb file="$tfile" width="$image_x" link="false" hint="false" overlay_position="$overlay_position" overlay="$overlay" sharpen="$sharpen" get_image_path="$get_image_path" html="class=\"$class\" alt=\"`$alt`\""}

To this

{thumb file="$tfile" width="$image_x" link="false" hint="false" overlay_position="$overlay_position" overlay_position="5" overlay="images/watermark/site.gif" sharpen="$sharpen" get_image_path="$get_image_path" html="class=\"$class\" alt=\"`$alt`\""}

Create a watermark image and put it in images/watermark

To change the image name just change this (site.gif) in the product_thumbnail.tpl

There might be better ways of doing this some others might like to add to it.