All the Windows Spotlight images on your PC are stored in a folder called Assets, deep in your user profile. Another method (this one's easier) is to use a third-party app like Dynamic Theme.
You may also run System File Checker to replace potentially corrupted system files. If in spite of being connected to the Internet, you face problems, you may want to reset Windows Spotlight ...
Turn on Windows Spotlight Like What You See Windows Spotlight ... you’ll have to carry out the following : Select all files inside that folder, then move them to the Recycle Bin and permanently ...