Sorry to be techy about it. I just don't know where art history would be today if this start a centry or two earlier. Where do ynou draw the line... did you get permission from the designer of your sweater to use it in your avatar? Did you cut your own hair or does the design belong to someone else? A lot of the stuff in the RMP store uses textures sampled off other peoples material such as building exteriors, other stuff relies on replicating designs by real world designers for things such as cars or shoes. That is commercial stuff and copyright is mainly an issue of commerce, that is why there are provisions for fair use... protection is extended somewhat analagously to patents, to provide exclusive commercial within strict terms... not to education and art.