How to add wallpapers to Kindle Fire? Where do I add/delete pictures so the Kindle Fire will randomly select it as a wallpaper for the device?
Someone over at the XDA Forums already discovered how to do that. See link to the thread below.

I strongly advise to follow this guide only if you know your way around the procedures mentioned (repacking &amp; zipaligning an APK file, file system operations with root permissions) and wouldn't mind jumping through several hoops to recover your device if the process fails.

XDA Thread - [Guide]Changing Kindle Wallpapers!