I think I know the answer to this question, but I've just discovered a photo of mine that has been used on a cover of a CD. I've only sold it once through Shutterstock (I got 10 cents for it). It is marked as editorial. As the image is of a sculpture with wording from a poem on it. I would assume that usage on an album cover is not classed as editorial, but commercial?
I am going to write to the person concerned to ask where he purchased the licence (the shot is with 2 other libraries), but what would you do under these circumstances?