Change desktop wallpaper to all client computer

1. open group policy management


2. Right click and edit on the Default Domain Policy


3. Select User configuration - Policies - Administrative templates - Desktop - Desktop


4. Double click Desktop wallpaper on the right pane
 

5. Place your background image file on a shared folder.


6. [I don't know this command is necessary or not] Run : gpupdate /force

7. Logoff and login again (Or restart) on the client computer



My environment :
Server : windows server 2008 (domain controller)
Client : windows XP (join domain)