MysticThumbs - MysticThumbs generates thumbnails of many image types not natively supported by Windows.
DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
Pictus - Pictus is a fast, free image viewer that enables Windows to see thumbnails of supported formats, such as PSD. Give it a spin today!
FastStone Photo Resizer - Convert and Rename images in batch mode Support JPEG, BMP, GIF, PNG, TIFF and JPEG2000
Icaros - Icaros is a collection of lightweight, high quality, Windows Shell Extensions
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.