Rhythmbox

Rhythmbox On Ubuntu
Plugins - Desktop Art

Ensure that you have a window manager like Metacity activated

If the artwork still doesn't display on the desktop try the following:

 Method One 

Ensure that Rhythmbox is not running

Edited the following file:

/home/username/.gnome2/rhythmbox/plugins/desktop-art/DesktopControl.py

Find the following line and alter it as shown in bold:

import rsvg # import rsvg

Save the file

Start Rhythmbox

 Method Two 

Open a terminal:

sudo aptitude update sudo aptitude install python-gnome2-desktop