These are all the Screenshots, Artwork images, and Wallpapers available on the official Diablo 3 website as of June 1st, 2009.  All are in the highest resolution possible.  The wallpapers are 1920x1200.  Screenshots are 1600x1200.  Artwork is all different resolutions.

I'm so excited, I can't wait until Blizzard releases this in 50 years.