Windows Thumbnail Cache - 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 or Filmstrip view in Windows Explorer) will have a Thumbs.db file. Folders with pictures also display previews on their icon when displayed in Thumbnail mode – the first four images in the folder at 40×40 pixels (or proportionally shaped), with a 1-pixel divider overlaid on a standard large folder icon. The Thumbs.db file is stored in OLE Compound Document format, the same format that many Microsoft Office products use.