Windows thumbnail cache

On Microsoft Windows operating systems (starting with Windows 2000), a thumbnail cache is used to store thumbnail images for Windows Explorer's thumbnail view. This speeds up the display of images as the smaller images do not need to be recalculated every time the user views the folder.

Purpose

Windows stores thumbnails of graphics files, and certain document and movie files, in the Thumbnail Cache file, including the following formats: JPEG, BMP, GIF, PNG, TIFF, AVI, PDF, PPTX, DOCX, HTML and many others. Its purpose is to prevent intensive CPU processing and load times when a folder that contains a large number of files is set to display each file as a thumbnail. This effect is more clearly seen when accessing a DVD containing thousands of photos without the thumbs.db file and setting the view to show thumbnails next to the filenames. Thumbnail caching was introduced in Windows 2000 ; wherein the thumbnails were stored in the image file's Alternate Data Stream if the operating system was installed on a drive with the NTFS file system. A separate Thumbs.db file was created if Windows 2000 was installed on a FAT32 volume. Windows Me also created Thumbs.db files. Beginning with Windows XP, thumbnail caching and thus, creation of Thumbs.db can optionally be turned off from Windows Explorer View Menu, Folder Options and checking "Do not cache thumbnails" on the View...
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