A free app for Android, by Photo Editors Zone.

The Photo Caller Screen HD Photo Caller ID – Fullscreen Caller ID app lets you change the look of your caller screen to something more pleasing. You can change the background image, add text, choose from a variety of themes, and set the default screen as the first screen that shows when you receive a phone call.

To use this, all you need to do is download it on your device and then open the application. From there, you can choose from the various themes that you can find and set as the default theme. You can also set your own photos as the background image.