Login Screen Background

Anyone know how to change the login screen background in 17.10.
I installed the lightdm-gtk-greeter-settings package, & changed the background using that, but nothing changed.
It seems the login screen is controlled by something else.
Any help would be appreciated.

See this thread:

Thank You.
Didn’t realize it was called “Slick Greeter”.
That’s solved my issue.

An easy way to customize it is with lightdm-settings (as opposed to lightdm-gtk-settings), a Mint app. A .deb, though, is here. Works just fine.