For some reason (I think it might have been me messing about) my Ubuntu install started opening folders using Eye Of Gnome image browser. So every time I went to open my Documents folder it would open up the image browser and show me the first image it found. This took me a while to fix as I wasn't sure what was going on really.
It turned out that the default application for opening folders was somehow changed to Eye of Gnome.
The solution is to right click the desktop and select create folder, giving it a random name. Right click the folder and select open with another application. Select file browser from the menu and make sure remember this application is checked. Remove the folder when finished.
After doing that it worked and me and my laptop are on speaking terms again :)