What is the thumbs.db file?
On computers running Microsoft Windows, a thumbnail cache is used to store thumbnail images for Windows Explorer when thumbnail view is enabled. This process allows images to display faster because these smaller images do not need to be recalculated every time a user visits the folder containing them.
The hidden file thumbs.db is a database file containing a small JPEG representing each of the thumbnails in a folder. Thumbs.db files are required by Windows to display a thumbnail for each icon. They are created automatically in the same directory as the thumbnails being viewed.
Can it be deleted?
This file can be safely deleted from any directory, although it will be recreated automatically if thumbnails view is still enabled and you view that directory again. We do have a section that shows users how to permanently stop Windows thumbs.db files from being created.
Is this file a virus?
No, thumbs.db is a Windows system file. However, like every file on your computer, it too can become infected. If you're concerned about a file being infected on your computer, scan it with antivirus software.