Software
Media RSS support
Any software that supports Media RSS should work, just copy & paste the RSS link to the software.
Variety support
My Little Wallpaper supports Variety through Media RSS. At the moment you can only get a RSS feed for search of your choice.
You can find more information about Variety here.
Python wallpaper changer for Linux
A simple Python script for downloading a random wallpaper from My Little Wallpaper and making it the desktop background. Can be set to run periodically with crontab.
Note that currently the only supported desktop environments are Unity, Gnome and Cinnamon!