How do I change the default logon screen in 12.04

Question

I'm wondering how I would go about changing the default logon screen (just the background) in Ubuntu 12.04. I can't seem to figure it out.

Answer 1

A solution I found to work is to replace the default background being used by lightdm:

> sudo cp /path/to/image.png /usr/share/backgrounds
> cd /usr/share/backgrounds
> sudo mv warty-final-ubuntu.png warty-final-ubuntu.png.old
> sudo mv image.png warty-final-ubuntu.png

This, however, is just a workaround and probably not the best solution. It is just the most direct way to do it assuming you don't need the default Ubuntu wallpaper.

EDIT: Also make sure that you set your image to have the same owner and permissions as the original warty-final-ubuntu.png (root,755),