Hey Charles
What do you mean by strech? If it is a wall paper and you want to strech it, please follow this instructions
Right click in desktop area and click properties on the pop-up menu. Click desktop tab. Select the wall paper you need on the background pictures list. Click the position and it will give you the following options..
Strec
Til
Cente
Select whatever you want
hope this helps
Siddhaarth.
