According to some websites, the lock screen pictures are stored at: C:\Users\username\AppData\Roaming\Microsoft\Windows\LockScreen_A
But I cannot find the LockScreen_A folder.
I guess this is not valid in Windows 8.1 anymore.
I am not interested in the c:\Windows\Web\Screen pictures (default pictures that come with the operating system).
I want to keep a copy of the current lock screen picture before setting a new one.