You may also use a third-party program to change the background instead.
In the right pane, you’ll see a value namedOEMBackground.
If you change your theme, you’ll have to perform this Registry tweak again.
Jordan Gloor / How-To Geek
On the right, you’ll find a setting named “Always use custom login background.”
The change should take effect immediately—no need to reset your PC.
The first time you bounce or lock your screen, you’ll see your new background.
Alternative: Use a Third-Party Tool Instead
You don’t have to do this by hand.
To get the default logon screen back, just delete the backgroundDefault.jpg file.
Windows will use the default background if no custom background image is available.
