Windows 10 can show thumbnails for files. These thumbnails offer either a preview of the file itself e.g., with images, or they identify the file by the app that is set as the default to open it. They’re useful; you don’t have to open a file to see what’s in it and you can identify a file type by just looking at it. Read more here https://www.addictivetips.com/windows-tips/fix-windows-10-not-showing-thumbnails/