Desktop/Wallpaper files are provided as ZIP archives; decompressed files are in JPEG format. File sizes are estimates, and refer to the size of the decompressed files.

You'll also find a new format desktop for Macintosh OS X systems, called DeskTop X. These provide special areas for drive and file icons on the right side of the screen, and for the Dock at the bottom of the screen. These special areas make your system icons more visible.