GPO - Set Desktop Background But allow users to changer

[Clippy]

We have a policy setup to use an image for our desktop background, this works, however we have decided that by default this should be the setting but if the user wants to change it then they can, everything else under the Admin Templates > Control Panel>Personalization & Admin Templates > Desktop>Desktop is "Not Configured" however I cant change the background image, any ideas how I get this to work, only running a win7 environment?

[Clippy]

In the group policy preferences registry item there is an option to **Apply once and do not reapply**. So configure the setting with a preference and check this box. The setting will then only be applied once per profile (for per-user policies).