Fresh Set of Images
Fresh Set of Images is a cross-platform image downloader that uses plugins for sources. If you set your computer's wallpaper folder to the download folder, you will always have a fresh set of images as a wallpaper.
Plugins are .py files that easy to create and are dynamically loaded by the program. You can view the plugin respository here: https://github.com/Mgamerz/fsoi_plugins
The program will eventually be able to run in the background, providing fresh images.