Gpo Lock Screen Image !!top!! -

| Name | Type | Data | |------|------|------| | LockScreenImage | REG_SZ | UNC path (e.g., \\server\share\image.jpg ) | | NoChangingLockScreen | REG_DWORD | 1 |

HKLM\SOFTWARE\Policies\Microsoft\Windows\Personalization gpo lock screen image

Then: