I found it, but it doesn’t seem to work, the text option does work though.
I upload a picture (watermark.png) to my images directory, link it and use the gallery > manage gallery > Set watermark. It says successfull but they won’t show.
I guess it’s a problem with the linking to the image since it doesn’t show up in the preview in the watermark options. I tried several paths but it doesn’t seem to work.
Any suggestions?