https://www.dropbox.com/s/wwy0qzey0vl4fjq/Davids_fancy_Log-in.jpg?dl=0

I wish all Linux desktop distros had more options for theming the login screen.

I am using Xfce ( in Rawhide ), and assume the procedure is the same in other desktop environments.

The trick ( I think ) is that you have to have root access to change the image

/usr/share/backgrounds/default.png

I copied my new image ( mountain-valley.png ) next to "default.png" in that same folder.  It MUST be a "png"

Then renamed "default.png" to "defaultx.png" 

and then renamed my new image "default.png.". 

Logged out and it was there.

D.L.