Windows is no longer creating new thumbnail images

It is often caused by corrupted thumbnail cache.

Make sure Windows is set to show thumbnails, not icons:

Open File Explorer > View > Options > Uncheck "Always show icons, never thumbnails" > OK/Apply.

Open Run menu and copy-paste cleanmgr and hit the Enter key.

Select C Drive.

Select Thumbnails and click OK.

Restart your PC.

You may also open Command Prompt as Admin and copy-paste the following commands:

taskkill /f /im explorer.exe
del /f /s /q /a %LocalAppData%\Microsoft\Windows\Explorer\thumbcache_*.db
start explorer.exe