FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
Fragment - A powerful image viewing suite with advanced metadata info
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
ImageGlass - You can use Image to view your digital images and photos of many different formats.
JPEGView - JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images.