Comment 8 for bug 968268

Running 12.04 with the new Unity Greeter that shows your wallpaper on the login screen.

Something else to think about with all this is that if the "Pictures Folder" really means ~/Pictures then when you have an encrypted home directory, these pictures will not appear at the login screen. Likewise if adding a picture means adding a pointer to it under the .cache directory it will also not appear on the login screen.

Ideally, there should be a way, even if it requires sudo priviledges to add wallpapers to /usr/share/backgrounds. If you this is a separate issue, let me know and I'll open a new issue.