Instead of pre-defined placement, would be nice to be able to drag & drop the watermark image for placement

I like the program. Apart from the previously mentioned sizing issues, it works great.
Only thing I would change is the ability, once the watermark image is selected, to drag it around the photo and place it exactly where you want, instead of only in pre-defined positions.

Other than that it is easy, intuitive and quick. A keeper for me.