How do I change my login screen on lubuntu?

Solution 1:

If you are using LUbuntu 19.10 as I am then the sddm search lead me to "https://forum.kde.org/viewtopic.php?t=138785". Cobber said that he changed this "/usr/share/sddm/themes/breeze/theme.conf" file.

Going into my own settings I found this folder "/usr/share/sddm/themes/lubuntu " Where I had a file called "wall.png" and a file "them.conf" with the command "background=wall.png". I just changed the picture to another one that I called wall.png and it used the new picture as my background.

Hope this helps. Lubuntu 19.04 probably will work the same since they are practically the same but I did not actually test it.