You Can Fix It

This will show you how to specify a BMP or JPG image of your choice as thedesktop background wallpaper in Windows 7 to be displayed on all users’desktops on the computer. You will also be able to specify that the wallpaper image position to have the center, fill, fit, tile, or stretch style on the desktop. The options to change the desktop background in personalization will not be grayed out, but they will not change anything after you have specified a desktop background in this tutorial.

This will also disable the Set as desktop background (image on computer) or Set as Background (image on website) option when a user right clicks on a image. It will not be grayed out, but it will not work.

Open the Local Group Policy Editor.

In the left pane, click on to expand User Configuration, Administrative Templates,Desktop, and Desktop

To Not Specify a Desktop Background The default setting is to allow users to change their own desktop backgrounds

Select Disabled or Not Configured, and click on OK.

To Specify a Desktop Background and Prevent Change

Select Enabled

In the Wallpaper Name: box, type in the full path of a BMP or JPG image that you want displayed as a wallpaper for all users. For blank wallpaper enter an invalid path

In the Wallpaper Style: drop down menu box, select if you want the wallpaper to be the Center, Fill, Fit, Stretch, or Tile style on the desktop

Click on OK
Close the Local Group Policy Editor window.
Restart the computer