How to change login screen in Ubuntu MATE?
 

Hi all. I hope this is the right place to ask this question.

I love Ubuntu MATE so much that I decided to keep it as a single OS on my computer. The only thing that I wanted to change is the login screen background. I would like to have my family's picture on it. Can someone help me with this, please? I don't really know how to use linux terminal with command lines, so please bare with me.

Very simple. Just right-click on an empty area of your desktop and a menu will appear. The final item is the one that allows you to change your desktop appearance.
You can then set your family's picture as the desktop background.
jdk

Hi jdk,

I was able to change the desktop background from the default picture. The problem is I can't find a way to change the background at the login screen. I don't care much to look at the green ubuntu mate logo when I enter my password to get into my desktop.

It should change before you log in if you just wait a few seconds. It starts out with the default screen and then changes to your selected background picture a bit after the login text boxes have appeared.
jdk