Windows 10 Default System Lock Screen Location so you can change it. - Microsoft Community

i searched everywhere information thought post others.

setting custom lock screen in windows 10 bit of pain can done. organizations , want change regularly.

 

by default it copies jpg files c:\windows\web\screen directories, admin can't read, the actual location uses from 

c:\programdata\microsoft\windows\systemdata\s-1-5-18\readonly\lockscreen_z (or letter)

when set gpo - control panel - personalization - force specific default lock screen , logon image = enabled

it sets following reg key hkey_local_machine\software\policies\microsoft\windows\personalization

regsz  = lockscreenimage

valuedata = path

this should copy file shared location c:\programdata\microsoft\windows\systemdata\s-1-5-18\readonly\lockscreen_z

i find unreliable if file name doesn't change have system sccm task blitz jpgs in folder , works , copy new ones again. otherwise copies once , never updates if update jpg file.

Windows / Windows 10 / Windows settings