I'm not sure ssmypics.scr exists in W7, I know I don't have one so you may not be replacing it, just copying the file there.
But windows\system32 is likely protected (normally you see a lock next to the folder in Windows Explorer); so if you get an error when you try to copy the file to system32 then you would first need to "Take Ownership" of the folder.
The easiest way to Take Ownership is to install the
Take Ownership script and then in Windows Explorer you right-click on the folder and choose "Take Ownership" from the context menu.