Tag That Photo - Your Photos in Your Control by Tag That Photo Software. Face Recognition, Privacy, Tagging and more.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
digiKam - Professional Photo Management with the Power of Open Source
JPEGView - JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
IrfanView - IrfanView ... one of the most popular viewers worldwide.