Sorry, but again, I don't consider wallpapers Art. Sorry.
Some wallpapers have absolutely nothing artistic to them and are still good wallpapers.
But yes, most piece of art can be placed on the background of your desktop. It doesn't mean they will be good wallpapers though. The purpose of a desktop is to have icons sitting on them, and certain work of art are too busy and you lose the icons on them.
But yes, just about any piece of art can be modified and arranged into a good wallpaper.
Don't take me wrong. I don't know if I can't make myself clear because I don't speak English good enough, but I think that some skins, wallpapers, chairs, cars, bridges, buildings, can opener, sinks, shoes, etc. are absolutely fabulously beautiful. They have some truly great artistic merit. But it does not define them as "art".
Point to a painting and ask me "What is that?" I'll say "It's art"
Point to a wonderfully beautiful chair and ask me "What is that?" I'll say "It's a chair"
But the thing is, that even a bad piece of art is still Art.
How can I explain this?
I can print a Monet and stick it on a chair. What will I get? A chair with a print of Monet on it. Not Art.
If I scan a Monet and put it on my desktop, what will I get? A wallpaper with a painting of Monet on it. Not Art.
Understand the difference? Yes, you can have Art on a wallpaper, but a wallpaper is not a piece of art in itself.