digiKam - Professional Photo Management with the Power of Open Source
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
JetPhoto Studio - JetPhoto Studio is a sleek and easy-to-use digital photo software that allows users to manage their photos in an attractive, intuitive mode and turning a sometimes frustrating chore into a fun and easy way by clicking only several steps.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Smart Pix Manager - Smart Pix Manager is a powerful and reliable solution for the management and viewing of all documents, common images, sound (WMA, MP3), and video files (AVI, MPEG), etc.