there were a few of those photomanips in the gallery, the last time I checked. I assume the reason they're allowed is that the actual copyright holders are unaware of them, hence they haven't brought it to yer attention. it probably belongs in a copyright forum with an actual copyright lawyer to tell us, but to post such a photomanip, the manipulator would need both a model release from the subject of the photo, as well as copy permission from whomever owns the original photo, IMVHO.