On Sun, 24 Jun 2018 20:02:35 -0400, Paul wrote:

The answer is quite simple.

C:\Users\UserName\AppData\Local\Packages\
Microsoft.Windows.ContentDeliveryManager_cw5n1h2tx yewy\LocalState\Assets

ff782ce3c9a149c1a13d00b69219712970f9f85d549afb5e4c 66c213aa072f41 === a JPEG etc.

Hi Paul,
I think there are a few locations for "lockscreen" files, where the
location matters depending on the particular question asked about them.

%WINDIR%\Web\Screen\.
%LOCALAPPDATA%\Packages\Microsoft.Windows.ContentD eliveryManager_cw5n1h2txyewy\LocalState\Assets\.
C:\ProgramData\Microsoft\Windows\SystemData\S-1-5-21-*\ReadOnly\LockScreen_0\.

Open an Irfanview window, drag and drop one of the bigger (higher byte
count) files in the directory onto Irfanview. If it asks to
put a file extension on the file, *deny* this request, since you
don't want to affect the file in any way while visiting. I tried
turning off that Irfanview request dialog, and the control for it
didn't work.

In my "Assets" folder, mine were all PNGs, where very few (almost none)
were even remotely related to the lock screen images (but a couple were the
current lock screen AFAICT).
http://img4.imagetitan.com/img.php?image=18_assets.jpg

The people answering the question, knew what they were
getting into when they started. As it's like Microsoft
to obfuscate stuff. Nothing to apologize for.

Exactly. While I don't normally bother with decorative niceties such as a
lockscreen photo, my interest was piqued by the question where I tried to
dig further into what Microsoft was actually doing, what they were
changing, where they were storing the files, when they changed those files,
etc.

It's all part of Usenet working well together, as it did on this thread,
where the worthless trolls, surprisingly, have shied away from this thread
(perhaps partly due to the strategic troll-shaming effort underway).