this script will get a new image from reddit every period and write it to an ixisting image on you Hard drive, if you set this image as your wallpaper you will have a constantly changing desktop wallpaper from the amazing subreddit called EarthPorn, they post grazy beautiful images of our mother earth.i tried this script on a linux Centos 6 machine with GNOME/GTK2 Interface
Full script with docs : https://github.com/blazeeboy/RubyScripts/tree/master/2014-5-12