Since I upgraded to Ubuntu 13.10 I can't find a way to chose a custom picture as desktop background.
I tried System settings -> Background, but this menu does not provide any file picker to choose a picture but shows only the preinstalled pictures:
Or an empty window:
I can't find the options to set how the picture ought to be displayed either (like stretch or scale)
Do I have to install Cinnamon desktop just to be able to change my background picture? How can I do it with Ubuntu?