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!
Visily - The easiest and most powerful wireframe software for agile teams.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Learn SpriteKit by Design+Code - Make a platformer iPhone game from scratch in Swift 4.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
PSD to Sketch Design Converter - Convert a Photoshop design to a layered Sketch file for free
JPEGView - JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images.