FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
ThumbView - ThumbView enables image thumbnails and tooltips in Microsoft Windows XP Explorer (does not work on...
digiKam - Professional Photo Management with the Power of Open Source
MysticThumbs - MysticThumbs generates thumbnails of many image types not natively supported by Windows.
FastPictureViewer - A hardware-accelerated image viewer for the modern Windows platform.
Icaros - Icaros is a collection of lightweight, high quality, Windows Shell Extensions