Windows 10 lock screen – display the own random images

To save the Spotlight images stored on your computer, see this procedure in this article:
How to save Windows Spotlight lockscreen images so you can use them as wallpapers.

To download almost all Spotlight images from Microsoft servers in a few minutes in high-resolution, see the SpotBright app.

Once you have the images, you can scan them for metadata that may contain information about where they came from.

There are various mechanisms for embedding metadata in images : IPTC, EXIF, XMP. This metadata is the only textual data contained inside the image.

EXIF is stored in the image by the camera and may contain information such as the GPS coordinates (if the camera has GPS, which most smartphones do). IPTC and XMP are added manually, as is normally done by professional photographers.

The best tool I have found for displaying that information is the free Picture Information Extractor. Try this tool on one of these downloaded images to see if Microsoft has kept some of that data or scrubbed it out.

If you have found such a useful tag(s), there exist image renamers that can use metadata tags to batch-rename the images.

I've been able to accomplish this by opening a folder here:

C:\ProgramData\Microsoft\Windows\SystemData\<SID>\ReadOnly\LockScreen_A

In this path, the <SID> is the security identifier for the user in question. This could be found by executing the following in a Command Prompt assuming this user is currently logged on:

whoami /user

In the end, the path would look something like:

C:\ProgramData\Microsoft\Windows\SystemData\S-1-5-55-555555555-555555555-5555555555-555555\ReadOnly\LockScreen_A

Also note that the LockScreen_A could be LockScreen_B (or alphanumerically incremented) if this is not the first lock screen background.

Though I work for Microsoft, I'm posting this as a user and not as an official endorsement of this method.