I'm trying to set the Windows 10 lock screen universally on a computer to a predefined image. To do this I'm using the GPO "Force a specific default lock screen image". This policy is Enabled and directed to a jpg located on a network location.
My problem is this policy doesn't set the image for the screen when there is no user logged on. When a user is logged on and locks the screen, it will show my custom image. But when they log off it reverts to a Microsoft spotlight image (some stacked rocks).
I've tried to remedy this by Enabling/Disabling the "Prevent changing lock screen image" and "Always use custom logon background" policies but no configuration seems to make a difference. I also tried changing the image to a local file instead of network.
EDIT: Windows 10 Pro 1511 Update (1607 not installed)