Comment 5 for bug 968268

Seb: we discussed this on IRC a few weeks ago and I mentioned that this is a known and intended side effect.

Also note that the wallpaper is never really added to the pictures folder -- just to a cache directory that appears under "Pictures Folder" in the UI (which is a bit of a lie, imho).

It is my understanding that the existing behaviour (after the patch) is the correct behaviour and that if you set an image as your wallpaper then you should not delete it after.