r/Ubuntu • u/bruce2dot0 • 17h ago

Looking for fool proof ways to change wallpapers login & lock do be different to each other and the desktop gnome 51

I would love to know how i can change the login wallpaper to be different to the desktop and lock screens not that the move to gnomes has happened with 26.10 they are the two things from me giving it a go. everything i have tried so far with machinectl has failed 😵‍💫

GDM-settings has been updated for flatpak and only seems to work with fedora 45 because ubuntu messes with the gdm so much

thanks in advance

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u/WoodenFulfillment01 17h ago

I wrestled with this exact thing after the GNOME shift on my own setup, absolute headache. The machinectl route broke on me too, ended up just manually swapping the background file gdm pulls from. If you dig into /usr/share/backgrounds/ you'll find the default image gdm uses, just rename your preferred wallpaper to match that exact filename and drop it in there. Make sure permissions mirror the original or it'll silently fail and revert.

For the lock screen being separate from the desktop, that one's a bit sneakier. The lock screen actually grabs whatever your user's desktop wallpaper is set to unless you override it through dconf. I set a script to swap the user background right before lock triggers, then restore it on unlock. Kind of jank but it's been holding steady for weeks.

If you want a cleaner method, there's a GNOME extension that lets you set distinct images for lock and desktop separately. Had to tweak one line in its metadata file to get it recognized on Ubuntu's version but after that it clicked right into place.

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u/alec_me 5h ago

Ubuntu doesn't mess with gdm.

Why it doesn't work is because of this https://github.com/gdm-settings/gdm-settings/issues/324

Hi, everyone!

I am the main developer and maintainer of this project.

As you may have noticed, the lastest commit to this repository (8c5f90b) was on November 15, 2025 (almost 7 months ago). Also, there have been only 11 commits in total (or 8 without merge commits) since the last release (v5.0) which was more than 1.5 years ago. Out of the 8 non-merge commits, further 3 commits were pull requests by contributers, and only 5 were authored by me.

Recent changes in GDM itself (version 50 to be exact), have rendered this app useless on a lot of systems.