Locking wallpaper on an android tablet running ice cream sandwich

[djsmiler]

We have just purchased some cheap tablets as a test.

I have managed to lock down all the settings with an app called app lock and also K9.

The only thing I am unable to do is stop the users from changing the wallpaper.I am hoping to be able to put the schools official desktop on and make it the default.

Does anyone know of a way to achieve this.