MMMOOO let me know that they have released a free BlackBerry application called Wallpaper Shifter. As the name implies, Wallpaper Shifter automatically rotates through your selected images and displays them on your homescreen at your desired interval. According to MMMOOO, this app seamlessly changes your wallpaper without using extra memory or battery power.

Wallpaper Shifter is available as a free download in the store for all BlackBerry devices running OS 4.7 and higher. Let me know how it works for you in the comments!