The background image of the login window cannot be changed

[Thiesen]

After upgrading from Ubuntu 20.04 Mate to 22.04 Mate, my custom wallpaper was replaced with the default one. I can make a change via the menu, but it stays with the default background image.

[Norbert (nrbrtx)]

Please run

apport-collect 1970081

[sandra (dandas)]

I have the same problem, both after upgrading and after a new installation. Ubuntu Mate 22.04

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[sandra (dandas)]

In the meanwhile I've found a workaround: i copied the picture i want to use as lightdm background on /usr/share/backgrounds/ubuntu-mate-jammy and renamed it with the system default image name.

[Ubucolors (ubucolors)]

In Ubuntu Mate 18.04 there was a application to change the login screen options, i think it was called "login screen" ? In "Preferences" it was found on in the top section.
Perhaps this app is simply missing in 22.04 ?
On the net we can fount different how-to's to change the login screen background on Ubuntu and Ubuntu Mate 22.04 but to complicated for most of us.

[AppLEaDaY (andrea-grillini)]

Here's the supposedly final solution:

(sudo) apt-get install lightdm-settings slick-greeter

and then

killall -HUP mate-panel

"Login Window" will automagically appear in the "Administration" section of "Control Center".

Thanks @ubucolors for confirming it was a matter of something no more available.

[AppLEaDaY (andrea-grillini)]

I was hasty, I didn't realize I just found a way to add the missing setup in the "Control Center". I'm stuck at the default image as well, though the setup actually writes the image I've chosen in a file in /etc. I'm working on it.

[AppLEaDaY (andrea-grillini)]

I recently realized slick-greeter was no more used, since "Arctica Greeter" was used instead. So I adopted the procedure pointed here: https://ubuntu-mate.community/t/how-to-change-lockscreen-and-login-wallpaper-with-arctica-greeter/24242/2 . So I could finally see the background I previously set in vain with "lightdm-settings". I cannot tell why the background in the password input boxes is white, though.

[Lucio Menzel (lucio-menzel)]

Me too, noticed this problem after upgrading from ubuntu 20.04 to ubuntu 22.04

The background picture I had selected in menu -> control centre -> Login Window is not the one shown, instead I see the jellyfish with green background picture

The display manager in use is called lightdm

The configuration files are under /etc/lighdm/

/etc/lightdm/
-- lightdm.conf
-- lightdm.conf.d/
-- slick-greeter.conf
-- users.conf

The background image setting is in slick-greeter.conf, I have the following values:
[Greeter]
background=/home/ubuntu/Pictures/mars.jpg
activate-numlock=true
show-a11y=false
show-power=false

Seems that the settings under /etc/lightdm/lightdm.conf.d/* take precedence, in fact, as an experiment I did

$ cd /etc/lightdm
$ sudo mv lightdm.conf.d lightdm.conf.d.old

after rebooting, now I can see the mars.jpg picture as the background of the Login Window as expected