There are thousands of resources to replace the background images on your iPhone, from apps to Web sites to your own photos. However, if you want to create a thematic look on your device, the easiest way to do so is with a tool like Pimp Your Theme. Providing a collection of different background and lock screen backgrounds, easy installation, and sharing features, this is a very good app for someone that wants a change for their device's background.
Pimp Your Theme offers a fairly simple solution when looking for new background or lock screen images for your phone. Open the app and you are presented with a few dozen options downloaded from the servers of the app developer. Backgrounds range from textures and color effects to animals and landscapes. There are quite a few paid-only backgrounds, but there are also a good number of free ones, and because all themes are built together and designed to augment your app icons, they generally look quite good when installed. Navigating the menus is quick and easy, too, and there are ways to look at more recent or more popular themes. On any theme screen you can test it to see what it would look like, share it with friends, or save it as a favorite before downloading it.
As a free background theme tool, Pimp Your Theme is a great alternative to some of the paid tools on the App Store. With plenty of options, an easy-to-navigate interface, and ample features for sharing and testing these themes, it's a great option for anyone looking to customize their iPhone screens.