Terminal: sudo nano /etc/lightdm/lightdm-gtk-greeter.conf
background = Background file to use, either an image path or a color (e.g. #772953)
Start Menu/ Preferences/Appearance Settings
Navigate to, and then select the image file (Picture), click "ok".
You can change the Desktop color, menu bar color, text color, toolbar font, etc., all from "Appearance Settings".
Last edited by Rive
on Sun Apr 03, 2016 6:02 pm, edited 13 times in total.