Customize LightDM with Themes and Backgrounds

LightDM is one of the login screens that you can use on your Linux machine. It’s a robust and reliable program, and while it does a great job of getting you from login to the desktop, one could argue the visuals are a little bland. The following will show you how to customize LightDM with themes and backgrounds to dress up that dull look.

Customize LightDM on Cinnamon

  1. To customize LightDM on Cinnamon, open your system’s control panel.
A screenshot showing Linux Mint's System Settings window.
  1. Scroll down to the “Administration” section, then click “Login Window.”
A screenshot showing the Login Window option in the System Settings window.
  1. Doing this will bring up a small window where the operating system will ask you for your account’s password. Write your password, then press Enter.
A screenshot showing the superuser authentication prompt in Linux Mint.
  1. The system will then open a large window that lists all the available options for LightDM. For example, you can click the rightmost button on the “Background” row to change the default image of your login screen.
A screenshot showing the LightDM Greeter settings for Slick.
  1. Turn off the “Draw User Backgrounds” switch.
A screenshot highlighting the user backgrounds toggle for Slick LightDM.
  1. Aside from changing the background image and color, you can also change the default theme of your LightDM instance. To do this, click the dropdown box beside the “GTK Theme” row, then select the theme that you want to use.
A screenshot highlighting the GTK Theme options for the login screen instance.
  1. Once done, you can close the Login Window prompt and log out of your current session to apply and test your new settings.
A screenshot of a custom Linux Mint login screen.

Good to know: Learn the difference between a window manager and desktop environment in Linux systems.

Customize LightDM on Unity

Unlike Cinnamon, the Unity Desktop Environment does not provide a graphical user interface for editing its LightDM greeter binary. In order to modify your login screen in Unity-based systems, you will need to pass LightDM’s configuration settings to its underlying “gsettings” daemon.

  1. Copy your custom image file on the default backgrounds directory for Unity:
sudo cp ./your-image.jpg /usr/share/backgrounds/
  1. Switch to the lightdm daemon user with the following command:
  1. Run the following command to disable the default user background behavior in LightDM:
dbus-launch gsettings set com.canonical.unity-greeter draw-user-backgrounds false
  1. You can now run the following command to set your custom background image:
dbus-launch gsettings set com.canonical.unity-greeter background '/usr/share/backgrounds/image.jpg'
  1. You can also set the overall theme for your LightDM session by changing the “theme-name” variable:
dbus-launch gsettings set com.canonical.unity-greeter theme-name 'Ambiance'

Note: You can find all the available GTK themes in your system by running: ls /usr/share/themes.

  1. Reboot your system to apply your new LightDM settings.
A screenshot showing a custom login screen in Ubuntu Unity.

FYI: Linux is more than just an end-user operating system for your computer. Learn some of the best server-oriented distributions that you can install today.

Customizing LightDM on XFCE

XFCE is a simple and lightweight desktop environment that uses LightDM as its primary display manager. Similar to Cinnamon, it provides a handy tool that allows you to customize your login screen without touching the command line.

  1. Click the XFCE menu icon on the Desktop’s upper left corner.
A screenshot highlighting the XFCE menu button.
  1. Click “Settings” on the Menu Window’s right sidebar then scroll down and select the “LightDM GTK+ Greeter Settings.”
A screenshot highlighting the LightDM Greeter Settings for XFCE.
  1. This will bring up a small prompt where the system will ask you for your user account’s password. Provide your account password, then press Enter.
  2. After that, click the button beside the “Image” label under the window’s “Background” category.
A screenshot highlighting the custom image prompt for LightDM.
  1. Select the picture that you want to set as your custom login background, then click “Open.”
A screenshot showing the file picker for the LightDM custom image.
  1. Next, disable the “Use user wallpaper if available” checkbox, then click “Save” to commit your changes to LightDM.
A screenshot highlighting the user backgrounds toggle for XFCE's LightDM instance.
  1. Reboot your system to apply your new settings.
A screenshot showing the XFCE login screen with a custom background.

Alternative LightDM Greeters

If the standard LightDM greeters (slick-greeter, unity-session and lightdm-gtk-greeter) aren’t to your liking, you can install alternatives. One option is to install the “other” default greeter, i.e. install the “unity-session” package on your Linux Mint machine, or the slick-greeter package on your Ubuntu system.

One thing to bear in mind is that each of these will install a fair number of new Unity or Cinnamon dependencies for you, so if space or performance is of utmost importance to you, these are not the lightest options. The following commands will install these greeters for you:

sudo apt install unity-session
sudo apt install slick-greeter
sudo apt install lightdm-gtk-greeter lightdm-gtk-greeter-settings
A terminal showing the installation process for slick-greeter, one of the many LightDM greeters available in Linux.

Display managers are just the tip of the iceberg when it comes to Linux customization. Learn how you can build your own minimalist Linux environment by installing Parabola Linux and running bspwm as your window manager.

Image credit: Jay Wennington via Unsplash. All alterations and screenshots by Ramces Red.

Ramces Red
Ramces Red

Ramces is a technology writer that lived with computers all his life. A prolific reader and a student of Anthropology, he is an eccentric character that writes articles about Linux and anything *nix.

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