FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
ImageGlass - You can use Image to view your digital images and photos of many different formats.
digiKam - Professional Photo Management with the Power of Open Source
Universal Viewer - Universal Viewer is an advanced file viewer for wide range of formats. Supported file formats are:
FastPictureViewer - A hardware-accelerated image viewer for the modern Windows platform.
Phiewer - Image Viewer - Phiewer is the easiest and fastest way to view your images, videos and even audio files.