Problem: If you install XDM as light Login Manager, cause XDM offers not
reboot/shutdown without Logon Access, XDM is very grey.
Solution:
– create JPG with your Display-Size (1024×768)
– save it at /usr/share/X11/image.jpg
– edit #sudo nano /etc/X11/xdm/xsetup
– add line:
xsetbg -onroot -fullscreen /usr/share/X11/image.jpg
– install #sudo apt-get install xloadimage
..enjoy xdm..