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!
Impossible I-1 Instant Camera - Take real polaroid photos with your iPhone
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Conmory - "Every Memory Counts!" Conmory is a social channel that lets you create a private space for you and your close-circle to connect special moments and generate new memories.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
Clocr - Clocr is the leading digital estate planning tool for online accounts. Create your online will, identify your executors. Secure and share your digital legacy.
JPEGView - JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images.