IrfanView - IrfanView ... one of the most popular viewers worldwide.
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Phiewer - Image Viewer - Phiewer is the easiest and fastest way to view your images, videos and even audio files.
ACDSee - ACDSee is an image viewer that uses very little system resources, and it has a small, sleek size that won't take up much space on your system.