How do I change the login screen in Ubuntu 16.04+?

The recipies for changing one's login screen in 14.04 [EDIT or in 15.04, 15.10] don't work in 16.04. The "custom" background shows for a split second and then fades to the Ubuntu one. So, how do I change the login screen background in 16.04?

[Edit: this post is not a duplicate because all other related questions specifically refer to previous versions of Ubuntu, and the solutions to those do not apply here (as they do not work on 16.04).]

7 Answers

You said:

The "custom" background shows for a split second and then fades to the Ubuntu one.

The greeter by default load the selected user background if it is available. A fade transition used to change between backgrounds of users including greeter default (for guest user). I think that the question should: How to stop lightdm greeter from loading the user background?

Be aware of two distinct greeters, default is unity-greeter. I noticed that some answer here in AU, don't mention this and mix up between them.

Using `lightdm-gtk-greeter`

GUI tool

Install the settings tool

sudo apt install lightdm-gtk-greeter-settings

Run it
```
pkexec lightdm-gtk-greeter-settings
```
In Appearance tab: Select the image
On same tab: Unckeck User user wallpaper if available
Save & Close

CLI tools

Open lightdm greeter settings file

sudo nano /etc/lightdm/lightdm-gtk-greeter.conf

Change it this way

[greeter]
background = /usr/share/backgrounds/Spring_by_Peter_Apas.jpg
user-background = false

Ctrl+o to save it then Ctrl+x to exit.

Using `unity-greeter` (default)

Same answer by Serg, I have tested it in a fresh VBox Ubuntu 16.04.

Change the background of the login screen

$ sudo nano /usr/share/glib-2.0/schemas/10_unity_greeter_background.gschema.override
[com.canonical.unity-greeter]
draw-user-backgrounds=false
background='/usr/share/backgrounds/Spring_by_Peter_Apas.jpg'
$ sudo glib-compile-schemas /usr/share/glib-2.0/schemas
$ sudo service lightdm restart

Some debug hints:

Purge lightdm-gtk-greeter settings

sudo apt purge lightdm-gtk-greeter lightdm-gtk-greeter-settings

Or you may want just disabling it temporary

sudo mv /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf.disabled

To enable it back

sudo mv /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf.disabled /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf

Restarting the lightdm is needed

sudo systemctl restart lightdm

Reinstall unity-greeter to remove any change in /usr/share/glib-2.0/schemas/com.canonical.unity-greeter.gschema.xml
```
sudo apt install --reinstall unity-greeter
```

Check if there any other dconf override file that take priority

grep -rn -e "com.canonical.unity-greeter" -e "background=" -e "draw-user-backgrounds=" /usr/share/glib-2.0/schemas/

To change the login screen in Ubuntu 16.04 I used the following:

gksu gedit /usr/share/glib-2.0/schemas/10_unity_greeter_background.gschema.override

Insert these lines:

[com.canonical.unity-greeter]
draw-user-backgrounds=false
background='/home/$USER/Pictures/1920x1080-TuxSuckingWindowsTetraWwallpaper.jpg'
# After changing use: sudo glib-compile-schemas /usr/share/glib-2.0/schemas

Where:

$USER = your user ID.
Pictures = your wallpaper directory.
1920x1080-TuxSuckingWindowsTetraWwallpaper.jpg = your image file name (can be .png format too).
# (comment) ... reminds you what to do after changing!

Save the file and exit gedit

Now compile the new login wallpaper with:

sudo glib-compile-schemas /usr/share/glib-2.0/schemas

Last step is to reboot.

Many thanks and credit to Serg: (Change the background of the login screen) Note on my system this no only changes the initial login screen but also the lock screen login as well.

Point and click with Nautilus to set login screen wallpaper

I wrote a script where you can navigate to a directory / image, right click on it and set it as login screen / lock screen background using Nautilus (file manager now called "Files"): Nautilus can set desktop wallpaper. How can it set login and lock screen wallpaper?

Run sudo lightdm-gtk-greeter-settings (if installed). Go to the Appearance tab, and select Background > Image.

Note: If you're selecting an image from your home folder and the folder's encrypted, it won't work, because /home/user hasn't been mounted yet.

As @OrganicMarble said, Ubuntu Tweak should do the trick. I installed it and in the Tweaks tab there is a tab called 'Login settings'. Unlock the page in the top right by entering the password and you can change the settings wallpaper. Since then my login and lock screens were changed.

This worked well for me on 16.04 LTS and without installing extra-software

In short: Open sudo gedit /usr/share/gnome-background-properties/xenial-wallpapers.xml and add your background image to the list. Then open the "Change background image" by right-clicking on your desktop, select the image and it's done for both working and login screen. Eventually restart to try it out.

To set the unity greeter as default, in Ubuntu 16.04 login screen, edit the file

/usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf

and change the "greeter-session" line to "greeter-session=unity-greeter"

Duo Step-

sudo cp Downloads/human_ubuntu-wallpaper-1366x768.jpg /usr/share/backgrounds/
sudo mv /usr/share/backgrounds/human_ubuntu-wallpaper-1366x768.jpg /usr/share/backgrounds/warty-final-ubuntu.png

Just lock and comment!