Debian/ログイン画面の背景の変更 - kobapan @ wiki

$ sudo mv hoge.jpg /usr/share/images/desktop-base/
$ sudo vi /etc/gdm3/greeter.gconf-defaults
-#/desktop/gnome/background/picture_filename	/usr/share/images/desktop-base/login-background.svg
-#/desktop/gnome/background/picture_options	zoom
+/desktop/gnome/background/picture_filename	/usr/share/images/desktop-base/hoge.jpg
+/desktop/gnome/background/picture_options	zoom
 

Debian7からは↓

$ sudo emacs /etc/gdm3/greeter.gsettings
+[org.gnome.desktop.background]
+picture-uri='file:///usr/share/images/desktop-base/hoge.jpg'
+picture-options='zoom'
 

$ sudo /etc/init.d/gdm3 reload
ログアウト