Changing GDM3 Theme and Wallpaper

Here is a quick hack for GDM3 to change the GTK controls and wallpaper/background image. This won't change the overall design/layout.

edit /etc/gdm3/greeter.gconf-defaults with a text editor as root or sudo.

Uncomment and edit the following lines by removing the # character.

/desktop/gnome/background/picture_filename /path/wallpaper.png

/desktop/gnome/interface/gtk_theme Aurora

Set the path to your background image on the picture_filename line. Set the GTK theme you want to use at the gtk_theme line. Make sure it is something valid that you have installed like Clearlooks or in my case Aurora. Also it's best to keep the background image the same size as your gdm3 resolution.

Then as root/sudo run dpkg-reconfigure gdm3