I want to change the background image of my Ubuntu (14.04) login screen, but Ubuntu doesn't display the changes. I tried changing the background in dconf-editor which resulted in there being no background just the vanilla Ubuntu color. And logging in resulted in the screen freezing in a kind of white noise mix of the login screen, after which I come in the desktop.
Then I tried it with Ubuntu tweak with no change.
I'm using the cinnamon desktop, I don't know if that may be the problem?
Anyone have any idea? Thanks