Comment 9 for bug 625357

I made a patch for gnome-desktop:
http://git.gnome.org/browse/gnome-desktop/commit/?id=6deb007f102d8ae9eabb10808f34d7129932dad3

The new version will fallback to load the default wallpaper if the user one is not available, not a fix for the original issue but it's better than having rendering issue and an empty background