[Linux (Gnome) only]: Lucast @ Gnome Look has created a script which uses my NatGeo wallpapers download script to get all the wallpapers for 2009 (~170 wallpapers) from the National Geographic website and then it creates a .xml file similar to the Cosmos wallpaper set in Gnome 2.28 which you can then use to automatically change your wallpaper every 29 minutes.

I have checked the script and is malware-free so it's safe to use!

I like changing my wallpaper automatically with a script (but alternatively, you can use Desktop Drapes or a similar app) every few minutes, but for that you need a lot of wallpapers.

You can already download hundreds of wallpapers with just one command but I really like the National Geographic wallpapers which are actually professional, amazing photos, so I made 2 really easy scripts which automatically downloads all the wallpapers (to date, the script will have to be modified when they add new wallpapers because the link is not fixed) from he National Geographic website.

To download all the National Geographic wallpapers from the 2008 or 2009 contests, simply download my scripts (download links at the end of the post), place them in a folder where you want to download all the wallpapers and run it like so: