Desktop & Screen Saver app in Sys Prefs keeps quitting, cant change bkground

Was using my parents comp and changing the backgrounds around. Put one on the comp, just a random .jpg and now the desktop patterns app in sys prefs quits whenever i try to open it.

Basically I need to change this screen. I put the 'gun show' pattern from rogue status as a joke and now it wont go away. My moms gonna take my '24 and give me this '20 if I cant make it change. Ha.

Thanks
-M.