All these Unreal desktop images are 256 indexed color, compressed, so you can enjoy a quick download and they tend to be less of a resource hog. *but they still look awesome =)
**For those of you running resolutions higher than 800x600: Don't forget to set your desktop colour to black and set it to center the image, as the image you are downloading is 800x600.

The Nali World Download it!

Put a four-armed Nali on your desktop. See a glimpse of his world in the background.
Only 79k to download!

Merc on the Hunt Download it!

A view of some of the Skaarj tech-filled levels with a Mercenary blocking your path to freedom.
Only 77k to download!

DeathMatch Hardware Download it!

Attitude and metal backlit by blue light. Check out this shot of 3 players ready to launch an assault.
Only 71k to download!