I'm running Xubuntu 12.04 and using the Unity greeter with LightDM. Everything works well except for I can never change the background. I've tried editing the .conf file, editing the gsettings as the lightdm user, even compiling an override file for com.canonical.unity-greeter. All of these fail, and I end with a dark purple background. I was able to get rid of the grid using gsettings, but that's about it. I've enabled switching user backgrounds, but that never works. I'm wondering whether this is Xfce/Xubuntu specific, or a bug.
Ubuntu – Unity greeter background on Xubuntu 12.04
backgroundlightdmunity-greeterxubuntu
Best Answer
Install dconf-editor from the Software Center and then "change" your background editing the entry in dconf. That way it will read correctly your background (probably xfce and gnome store the "background" value in different ways, so this way you are telling lightdm where is the background in the "gnome" way. I'm trying this right now