Thumbcache files are database files that are automatically generated by the Microsoft Windows operating system from Windows Vista onwards within the ‘hidden’ system directory located at the path \Users\[User Profile Name]\AppData\Local\Microsoft\Windows\Explorer\.
Images within the Thumbcache files are automatically stored when a folder on the computer or a device connected to it is accessed by the user using the Thumbnail or Icons view within Windows Explorer.
The thumbnail or icons view include small images in a gallery format that contain the content of any images within the folder being viewed.
Even when the original files are deleted from the folder, the automatically generated copy within the Thumbcache is not removed.
Due to them being ‘hidden’ and inaccessible, a normal user is unlikely to be aware of the existence of images within Thumbcache files.