Windows thumbnail cache: Difference between revisions

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{{Short description|Aspect of the Windows operating system}}

On [[Microsoft Windows]] [[operating system]]s, starting with the [[Internet Explorer 4]] Active Desktop Update for Windows 95 to 98,<ref name=PCWorld>{{cite web |url=http://www.pcworld.com/article/13357/windows_tips.html|title=Windows Tips|date=19 October 1999|work=PCWorld}}</ref><ref name=AccessData>[http://accessdata.com/media/en_us/print/papers/wp.Thumbs_DB_Files.en_us.pdf Thumbs.db files forensic issues: AccessData Corporation]</ref> a '''thumbnail cache''' is used to store [[thumbnail]] images for [[Windows Explorer]]'s thumbnail view. This speeds up the display of images as these 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 file format|BMP]], [[Graphics Interchange Format|GIF]], [[Portable Network Graphics|PNG]], [[Tagged Image File Format|TIFF]], [[Audio Video Interleave|AVI]], [[Portable Document Format|PDF]], [[Microsoft PowerPoint|PPTX]], [[Microsoft Word|DOCX]], [[HTML]], and many others. Its purpose is to prevent intensive disk [[I/O]], 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;<ref name=AccessData/> 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.<ref name=AccessData/> From Windows XP, thumbnail caching, and thus creation of Thumbs.db, can optionally be turned off. In Windows XP only, from Windows Explorer Tools Menu, ''Folder Options'', by checking "Do not cache thumbnails" on the ''View'' tab. In other versions of Windows, thumbnail caching can be turned off via [[Group Policy]]. Under Windows 2000, Windows Me, and Windows XP, a context menu command to force refreshing the thumbnail is available by right clicking the image in ''Thumbnail'' view of Windows Explorer.

==Thumbs.db==

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==External links==

*[https://thumbcacheviewer.github.io/ Thumbcache Viewer] – open-source thumbcache_*.db viewer

*[https://thumbsviewer.github.io/ Thumbs Viewer] – open-source viewers for both Thumbs.db (legacy mode) and ThumnailThumbnail Cache (modern)

*[https://github.com/AtesComp/Vinetto Vinetto] is a forensics tool to examine Thumbs.db files.

*{{webarchive |url=https://web.archive.org/web/20131116234204/http://www.thumbnailexpert.com/en/formats/windows-thumbnail-cache/ |date=November 16, 2013 |title=Windows thumbnail cache}} – Description of thumbs.db file