See the following page for the F17 Artwork Schedule: F17_Artwork/Schedule
This is the concept on which the default wallpaper in Fedora 17 will be based.
Early pre-Alpha packages
Note: In each desktop environment you need both referenced packages (one contains the actual images and the other contains desktop specific info to make it appear in BG selector).
Post Alpha Feedback & Refreshes
Widescreen (16:10; 1920×1200)
(Old) Standard (4:3; 2048×1536)
Normalish (5:4; 1280×1024)