When you start your Windows 10 PC, you may see some great images displayed as the background of the lock screen. You can click on the lock screen picture to proceed to log on your Windows PC. This is the new Windows Spotlight lock screen feature for Windows 10. Windows Spotlight will download and show users the great images from Microsoft Bing.com homepage. The Windows Spotlight will bring you different visual experience each time you open your computer. It will also let users vote if they like those images for the lock screen background so as to tailor the look of the lock screen for different users.
Windows Spotlight should be enabled on your Windows 10 PC by default. If you have not turned it on or it has been disabled somehow, you can follow below steps to enable Windows Spotlight on Windows 10 computer.
How to enable Windows Spotlight on Windows 10 PC?
Right click on the desktop on your computer screen, select “Personalize” from the drop down menu, you should then get to a screen with a navigation panel on the left. Click on “Lock Screen” from the left menu. You will then be able to preview your PC lock screen picture on the right. Change the setting from others to “Windows Spotlight” under the Preview picture section. See below screenshot.

How to download and save Windows Spotlight lock screen pictures on Windows 10 PC?
Windows Spotlight pictures or lock screen backgrounds would be saved but hidden in Windows 10. You can find them from this Windows Spotlight picture location or saving path:
C:\Users\{your name}\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\LocalState\Assets
Make sure to replace the {your name} with your real Windows account username when you open above Windows 10 spotlight backgrounds or wallpapers location in file explorer.
Alternatively you can also press the Win+R keys combination on your keyboard to launch the Run window and then copy and paste below line and execute in the Run window:
%localappdata%\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\LocalState\Assets
Another way to open the Run windows in Windows 10 is to right click on the Start button, then choose Run from the pop-up menu.

Now you will find the folder where all Windows Spotlight background pictures are saved in Windows 10. However they are all stored on your PC without any file extensions, so you will not be able to preview them instantly. Do not change the original Windows spotlight lock screen background pictures. You can create a new folder somewhere else, then copy spotlight pictures from its default location to the new folder. You can ignore those very small files, such as those less then 100KB. You can click the Size column to quickly sort all Windows spotlight pictures by size.
After we have copied windows spotlight background pictures to the new location, you will need to manually add .jpg as the extension to the Windows spotlight photos. To rename files in Windows 10, you can right click on the file you like to rename or change its file extension, then choose Rename from the pop-up context menu, then add .jpg after its original file name, or you can change its file name at the same time.
An easier way to batch adding file extension to Windows spotlight pictures
Open the new Spotlight assets folder where you have copied original Windows spotlight background pictures to. Press the Shift key on your keyboard, right click on somewhere blank in the new Windows spotlight folder at the same time, you will open the context menu. Choose “Open command window here”. After that the Command line prompt opens with the current folder opened. See below screenshot. You can find more specific instruction from this guide to open command prompt from current folder in file explorer for Windows 10.
To change file extension of all files in current folder on Windows PC, you just need to execute a simple command like this:
ren *.* *.jpg

Copy above code in to the DOS command line, then press Enter key on your keyboard, all your files in current folder will be renamed to files with jpg as their new extension.
Set a Windows spotlight lock screen picture as permanent one
As we have mentioned above Windows spotlight will change from time to time. When a new Windows spotlight picture is downloaded to your Windows 10 PC, it will replace the old Windows spotlight image. If you like to make certain Windows spotlight lock screen picture as permanent lock screen picture. You can firstly follow above steps to save the Windows spotlight lock screen image to your computer. Then copy it to the default Windows 10 lock screen wallpaper folder which should be C:\Windows\Web\Screen. After that, right click on the desktop on your computer screen, select “Personalize” from the drop down menu, click on “Lock Screen” from the left menu. You will then be able to preview your PC lock screen picture on the right. Change the setting from “Windows Spotlight” to “Picture“under the Preview >> Background section. Then find and click the Windows spotlight image from the “Choose your picture” image thumb preview section. When one picture is set as the new lock screen picture in Windows 10, it will be moved to the first in this thumb preview and selection section.

Set a Windows spotlight lock screen picture as desktop wallpaper
Just right-click on the picture file, then click “Set as desktop background” from the context menu. This will set your selected picture as the new desktop wallpaper on Windows 10 computer.