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!
Great option to other image editors and image creating software. It has a simple and intuitive user interface, yet supports both layers and 3D objects. Functional across all major OS. It is free, as in open source. It imports .PDN files created with Paint.NET without issues.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
GIMP - GIMP is a multiplatform photo manipulation tool.
JPEGView - JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images.
Microsoft Paint - Paint (formerly Paintbrush) is a simple, ultra-basic graphics painting program that is included...