It's been a week since Canonical released Ubuntu 25.04. At that time we also published an article about GDM Settings, a software that allows you to customize the GNOME login screen and modify it from top to bottom. Now, I have something to confess: I didn't get the kitten image with GDM Settings. The reason was that I was in a hurry and wanted to do it with the flatpak version. While it is true that you can get the GDM previous with the version from the unofficial repository, it is also true that there is another way.
It must also be said that What is explained here is not only valid for Ubuntu, but that's the reference we'll use. IN THEORY, and note that it's capitalized to emphasize its importance, it should work on any Linux distribution that uses GDM as a session manager, especially if you also use GNOME. The installation for full functionality and the ability to change the wallpaper with GDM Settings will be done through an unofficial repository for Ubuntu-based distros, but we'll also provide an alternative.
Installing GDM Settings on Ubuntu
To install GDM Settings on Ubuntu and derivatives, open a terminal and type these commands:
sudo add-apt-repository ppa:ubuntuhandbook1/gdm-settings && sudo apt update && sudo apt install gdm-settings
To launch the program, just search for it in the app drawer. You'll see a notification reminding you that we will be making changes that may be dangerous and you should only continue if you are clear that something could go wrong, and each person is responsible for it.
Change the login screen background
Option A: GDM Settings
To change the wallpaper in the session manager or GDM, simply open the "GDM Settings" app in the app drawer, then go to Appearance/Background. Clicking there, you can choose an image or a color. If you want an image, look for one with high quality (I wouldn't recommend anything lower than 1920x1080), select it, and then click Apply. The Ubuntu 25.04 wallpaper would look like this:
NOTE: : The flatpak version cannot change the GDM background.
Option B: Script for Ubuntu
There is another option, but it's a script that only works on Ubuntu and, at the time of writing, doesn't support 25.04. But it's easy to get it working. We'll start by downloading it with this command:
wget https://github.com/PRATAP-KUMAR/ubuntu-gdm-set-background/archive/main.tar.gz
Next, unzip the downloaded file, which will be in your home folder. You'll get a file named "Change-Gdm-Background-3.8.sh." If you run it by giving it execution permissions, dragging it to the terminal, and pressing Enter, it will tell you that Ubuntu 25.04 is not supported. It's very easy to add support, as 24.10 and 25.04 are almost identical.
We open that .sh file with a text editor. We need to look for a section that says "case $version in," and below it, the supported versions. The one at the bottom is Ubuntu 24.10, and if we launch it from 25.04, since this option isn't supported, it displays an error and exits. To prevent this error from appearing and allow us to continue, below the lines for 24.10, we need to add the lines for 25.04, specifically the following:
*"Ubuntu 25.04"*) /bin/echo -e "\e[1;32m |-| Ubuntu Version : $version\e[0m" gdmpath="gdm" call_gui_choice gdm_update user_login_change gdm_compile ;;
We save and close. Now, we start the script and enter our password.
Process
We will see a pop-up window like the one above that offers us options:
- Choose a background color.
- Choose a background image.
- Revert changes to the default state.
If we want to add an image, we'll choose the second option and click OK. This will open a dialog box for selecting the image. After choosing it, it will make the necessary changes, likely installing some packages, and then ask us if we want to restart the system (recommended), or just restart GDM. Here we can choose whichever we prefer, but it's best to restart.
With this, we'd have it. Even someone like me, who doesn't like changes much, likes seeing a login screen with a different image. Hopefully, in the future, it won't take so much work and we'll be able to change it from the distro's settings.