Abstract: Systems and methods are provided for storing and retrieving thumbnail images in a per-user/per-system thumbnail cache. One or more data files may be used to store thumbnail images of varying sizes. An index is updated with the location or locations of thumbnails for a particular file, the URL and modification time of which may be used as a key to finding the thumbnails within the index. Direct memory mapping of thumbnail images are provided. Concurrency techniques are utilized to maintain cooperative access to the cache among multiple processes. Cache contents which are orphaned or unused are reclaimed for use by newer or more frequently used thumbnail images.