How do I change Login Screen wallpaper in Ubuntu 21.04?

I used to be able to do this simply in 20.04 LTS, as there was an applet for it. How do I do this in 21.04? I can't seem to find anything on this any where! Why change\or hide this when it was so simple before?

Because they switched to a new greeter in 20.10 compatible with Ayatana Indicators and there's no GUI to change those setting yet. Reasons are mentioned in the 20.10 release notes.

There's a reason interim releases aren't LTS. They're paving the way for the next LTS, introducing new features, one at a time and things aren't expected to be perfectly polished.

You can edit the Arctica Greeter settings with:
sudo pluma /usr/share/glib-2.0/schemas/30_ubuntu-mate.gschema.override
Don't screw up while editing things though. Once you've saved your edits, run:
sudo glib-compile-schemas /usr/share/glib-2.0/schemas/


That did it! Thanks.

Yeah I usually don't jump in on interim releases that often any more but I liked the looks of this one somewhat and I wanted to see what the performance was like. Still had to switch to the Ubuntu Mono Dark icons but the Yaru Mate Dark controls are pretty sweet. I just like skeuomorphic design icons better. I like how they 'pop' on the screen. I know that others are more accustomed to the flat web look that's popular these days but I still like the explosion of color popping off the screen.

Performance has been quite nice so far.