How to Change the login Screen Background in Fedora 15?

Well Frnds I found that so many student wants to customize the login screen of fedora ......My new Post is related with it......
Just Simply Run the Following Commands in Terminal :-


1.Fisrt login in as root

su-

enter password

2. You need to install gnome-tweak-tool

          yum install gnome-tweak-tool

3. Now we make the gdm user available to make changes:-

          xhost +SI:localuser:gdm

4.How to change gdm login background:-
    sudo -u gdm gnome-control-center
And when you're done exit the gnome-tweak-tool or gnome-control-center and type:
Code:   # exit



Enjoy..........