Making a change to established user profiles using scripts

Hi all,

I am after a solution that will allow me to change a certain "thing" in all user profiles when they logon.

What i would like:

I would like to create a logon script that copies a bitmap image to windows directory for use as a background and then either using the script or a policy set the copied image as the background image for all users.

Is this possible?

Thanks

CyberIDentity