All prose and instructions are up to par. Extra info needs to be provided on picture options, per comment below. --shaunm
Matthias Clasen
matthias.clasen@gmail.com 2012
Jana Svarova
jana.svarova@gmail.com 2013
Petr Kovar
pknbe@volny.cz 2014
David King
davidk@gnome.org 2014
Ekaterina Gerasimova
kittykat3756@gmail.com 2014
Change the default desktop background for all users.

# Set custom background

You can change the default desktop background to one that you want to use. For example, you may want to use a background with your company or university logo instead of the default GNOME background.

# Set the default background

Create the user profile which contains the following lines:

# /etc/dconf/profile/user

user-db:user system-db:local

local is the name of a dconf database.

Create the directory /etc/dconf/db/local.d/ if it does not already exist.

Create the key file /etc/dconf/db/local.d/00-background to provide information for the local database.

# /etc/dconf/db/local.d/00-background

# Specify the dconf path [org/gnome/desktop/background]

# Specify the path to the desktop background image file picture-uri='file:///usr/local/share/backgrounds/wallpaper.jpg'

# Specify one of the rendering options for the background image: picture-options='scaled'

# Specify the left or top color when drawing gradients, or the solid color primary-color='000000'

# Specify the right or bottom color when drawing gradients secondary-color='FFFFFF'

To prevent the user from overriding these settings, create the file /etc/dconf/db/local.d/locks/background with the following content:

# /etc/dconf/db/local.d/locks/background

# Lock desktop background settings /org/gnome/desktop/background/picture-uri /org/gnome/desktop/background/picture-options /org/gnome/desktop/background/primary-color /org/gnome/desktop/background/secondary-color

Update the system databases:

    # dconf update

Users must log out and back in again before the system-wide settings take effect.