PressWin+Ito open Windows options then selectPersonalization.
SelectLock Screenin the menu on the left side of the screen.
Toggle the switch next to this option to copy your custom lock screen image to the sign-in screen.

Windows Timeline is a powerful Windows 10 feature that you should be using.Microsoft
This setting overwrites the default Windows 10 logo image with your customized lock screen picture.
Can I Make the Lock Screen and Sign-In Screen Different?
There’s no official way to create separate background images for the Windows 10 lock and sign-in screens.

Several unofficial apps have enabled this capability in the past, butWindows 10 system updateshave rendered them useless.
Do I Need to Change the Windows 10 Login Background?

Windows Timeline is a powerful Windows 10 feature that you should be using.Microsoft