Changing the background picture of another profile

[CountZero]

Is it possible to change the background picture of another profile without actually logging into that profile if you have admin privileges?

I'm looking to play a mild prank on someone for their last day but am not sure if its possible.

Thanks!

 

[NogginBoink]

Yes, but it's not easy.

You need to mount the ntuser.dat file of the target user in the registry. To do this you need read permissions on that user's profile, and to change it you need write permissions on their profile directory.