I've got a HUGE library of great-looking photos that I've been turning into iPhone wallpaper images. Since I'm doing it for me, I figured I'd post them for YOU in case you wanted to use them, too.
The top one is for iPhone 4S and the bottom is for iPhone 5 and up. You should be able to save it to your phone's camera roll, and from there, set it as wallpaper.
This edition features balloons in the conservatory in the Bellagio in Las Vegas.