The Canonical Design team is currently running a contest for beautiful desktop wallpapers for its upcoming Ubuntu Karmic Koala 9.10 scheduled to be released in October 2009. They have created a photo pool on Flickr where you can submit or just browse proposed backgrounds:
In our next release, the Karmic Koala (Ubuntu 9.10), we would like to include a set of high quality desktop backgrounds. In order to accomplish this we call on anyone and everyone to submit images which are freely licensed CC-BY-SA and follow the guidelines for inclusion.
Here are some more guidelines for the competition:
Avoid prominent use of the Ubuntu logo. It appears in enough places already.
No version numbers. Some individuals may desire to use an older theme, or use the latest theme in their older version of Ubuntu. Let your submission be about choice and do not use version numbers in your artwork.
Avoid text, it calls for attention too much and will likely look bad when scaled. Plus it can’t be translated easily.
Be careful with small patterns, they might become uneven when scaled.
Consider how the wallpaper will interact with the panels, icons and windows.
Show restraint in your use of color tone and contrast. The wallpaper sets the scene for other elements, it is not the main act.
So what are you waiting for? Grab your SLR and launch your GIMP!