Prevent users from changing the desktop themes, background and other visual settings on a Windows 8.1 PC.
An administrator account.
Any version of Windows 8.1 allowing access to the Group Policy Editor
Open the Group Policy editor
In the window that opens, go to User Configurations > Administrative Templates > Control Panel > Personalization.
Double-click on Prevent Changing desktop background and select Enabled.
You can also enable other restrictions from this menu: