Kiwi Random Wallpaper is a small application that enables you to change your wallpapers regularly from a huge wallpaper database from the Internet. It is a freeware wallpaper downloader application that's well-designed and light on system resources.
Here are some screenshots to illustrate the features and user interface of this application:
Bing Wallpaper
Lively Wallpaper
DisplayFusion
John's Background Switcher
BioniX Wallpaper