On Microsoft Windows operating systems, starting with the Internet Explorer 4 Active Desktop Update for Windows 95 to 98, 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, GIF, PNG, TIFF, AVI, PDF, PPTX, 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; 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. 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. 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 Thumbs.db files are stored in each directory that contains thumbnails on Windows systems. The file is created locally among the images, however, preventing system wide use of the data and creating additional data load on removable devices. Windows XP Media Center Edition also creates ehthumbs.db which holds previews of video files. Each thumbnail created in a directory is represented in this database file as a small JPEG file, regardless of the file's original format. The images are resized to 96×96 pixels by default or a proportional miniature of their original shape for non-square images, with 96 pixels on the longer side. The size can be controlled by a setting on Windows Registry. Each folder with initiated thumbnail views (that is where they have displayed a Thumbnails