iOS 7 does a pretty good job taking just about any image you have and making it work with the new parallax background effect, moving your image behind your icons. But there are tricks to making it work well, and there are also some fantastic photographs out there on the internet. Combine it all together and you get FreeiOS7.com's collection of parallax wallpapers. They've sized them for both the iPhone and iPad, so head on over and check 'em out. Easiest is to do it from your iOS 7-based device, then save your favorite image(s) to your camera roll and... off you go!
Check It Out: Free iOS 7 Parallax Wallpapers for Download