I have tried everything from the program posted here to signing in and nothing seems to work And I HATE that sunlight shining through the window log in picture....I have a cool jpeg I want to use but it wont let me. Help? I am running Windows 10 Professional on my desktop and an upgraded version of windows 10 home on my laptop (upgraded from windows 8.1 to windows 10) So far nothing from the net or the program here seems to work
Go to Settings > Personalization > Lock Screen and scroll down. You should see a toggle under Show Windows background picture on the sign-in screen. Turn this toggle off and the next time you log in, you'll see a solid color instead of the Windows logo on your log-in screen.