Making LightDM use the wallpaper (Updated)

Variety 0.4.15 added some options to help make sure the wallpapers set by Variety are also used by LightDM at the login screen.

Probably you are reading here because it does not work for you? Please read below.

1. This setting has been tested to work on LightDM, the default login manager coming with Ubuntu. If you use another login manager, this setting might or might not work for you.

2. IMPORTANT. If you have edited the set_wallpaper script in the past (~/.config/variety/scripts/set_wallpaper), Variety's upgrade mechanism will not update it automatically and the LightDM support options will not work. If this is the case, please rename or delete your current set_wallpaper script and run Variety again - it will automatically recreate it with a current version. You may them manually merge-in your custom changes if there is still need.

3. LightDM is picky. There are some conditions that have to be met so that it can use and show the background picture:

3.1. LightDM needs to have read permissions over the file, which generally means that the file should be readable by everyone.

By default, Variety uses the default download location ~/.config/variety/Downloaded, and only you have access to those files, not other users.

3.2. The file should not be in an encrypted Home folder.

Even if the file permissions seem right after your login, LightDM cannot read from inside your encrypted home folder. In this case, the wallpaper image must reside outside of your home folder, in a public place such as /usr/share/backgrounds

3.3. The file needs to be on the main drive, not on a mounted partition

For example, my Favorites are on a mounted external partition and lightdm does not use those pictures from their original location. Probably the mount uid, gid and masks options play a role here - maybe this boils down to the same as 1 - that the other users don't have the proper permissions over these files at the time of login.

Variety recommends the following setup and the GUI for the LightDM support option will also guide you in this direction:

If your home is not encrypted, place the wallpaper in ~/Pictures (directly inside it, not in a subfolder). Also make sure this folder is readbale by everyone.

If your home is encrypted: Using superuser priviliges, grant yourself write access to /usr/share/backgrounds, and set Variety to place the wallpapers there. LightDM will use the files from there OK.

Alternatively, create some global folder on the root partition (e.g. /pics), readable and writable by everyone, and then configure Variety to copy wallpapers there.