Yeah, the trouble with watermarks is either
a) They're not on the image, so you can just paint over them with the background colour or snip them out or
b) They are on the image and ruin it.
Though I've seen some from IGN are just a slight shift from the background colour you can't really see it unless you're looking for it (I think it's a photoshop template of some kind that slightly alters the colours it's placed over). This had one rather infamous consequence when Capcom couldn't find a file copy of the boxart to a game they were re-releasing:
Look in front of the wolf's mouth if you can't see it. And yes, it was actually released in stores like that.