ThumbView - ThumbView enables image thumbnails and tooltips in Microsoft Windows XP Explorer (does not work on...
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
MysticThumbs - MysticThumbs generates thumbnails of many image types not natively supported by Windows.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Icaros - Icaros is a collection of lightweight, high quality, Windows Shell Extensions
Seer - A Windows Quick Look Tool in Qt.