Python script for automatic background changing in Ubuntu

Could you write(or hint at) a Python script that changes the Ubuntu desktop background automatically from a website(like Flickr or deviantArt)? How can I start the script at st开发者_运维百科artup?

Not python but a direction: http://www.webupd8.org/2009/09/real-time-earth-wallpaper-for-linux.html