how can anyone lay claim to an image these days anyway? If they didn't borrow it, it was more than likely heavily influenced by something they saw or the aliens that are beaming signals into their head. In any case, it becomes something new and unique in the collaborative process, and should not be seen as an individual piece by a single artist (unless it is a gridhog piled upon a gridhog, then it is a hyper gridhog and only the artist responsible can be called to account for such actions.)