What would be the restriction, if any, for making wallpapers out of well known works of art and posting them? (eg: Van Gogh, Rembrandt, Vermeer) Is this something that would be allowed if the proper credit was given? I know that there are several well known works of art that I am fond of and would love to have as a desktop wallpaper. Would this go against the goal of the site?

I can see that it might not be the best idea to post these images under your regular username, as they do not belong to you personally. Maybe a gallery for "Famous Artists" or something to that effect that could seperate them from personal works. Again, this may not be something that is feasable or even desired for the site. Just a thought that popped into my head while looking around today.