Windows Vista stores thumbnails in the following directory: \Users\\AppData\Local\Microsoft\Windows\Explorer
This directory contains following files:
- thumbcache_32.db, thumbcache_96.db, thumbcache_256.db, and thumbcache_1024.db
Thumbnails are stored in thumbcache_NN.db files in different formats (e.g. BMP) and can be extracted using file carving. There are several tools that can work with Vista Thumbcache: dmThumbs, Thumbs.db Viewer, and FTK. Unfortunately, there is no information in the thumbcache that can easily link thumbnails with original files in all cases. One of the ways to link thumbnails with original files is to use Windows Indexer (Windows.edb) database.
Thumbcache format is described here.