XnView MP stands for Multi Platform = it is available for Windows, Linux and MacOS. It is a continuation of the older XnView Classic. In my opinion it is a great alternative to Windows photos app or any Linux image viewer that comes preinstalled. I even think it is an alternative to IrfanView. It is really fast and simple to use, supports more than 500 image formats, has built in folder browser, image converter, editor... AND MORE!
Eagle App - Unify your creative inspiration in one place. Store anything – inspiring images, design mockups, illustrations, screenshots and more.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Pixave - The ultimate image organizer for the Mac.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
Ego - Ego gives you one central—and lovely—location to check web statistics that matter to you.
JPEGView - JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images.