I am curious as to the steps necessary in order to obtain permission for the use of a piece of art for an album. The image in question is actually a "derivative" of an original piece by another artist. This artist had permission to make a derivative version because the original image creator embraced this derivative version on is website and they know eachother. My question is, who do I need need to ask for permission of the derivative? The original author/creators OR the artist that created the new derivative version that we actually want to use, or both. Who gets paid for its use? The original is a animated style computer image of an object in the desert, and the derivative is basically the same thing, but a 3D "real life" looking interpretation of it. Either way, I would like to take the proper steps and file things correctly in order to avoid any kind of infringement. Thanks for your help!