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!
Aoao Watermark for Photo - Aoao Watermark for Photo is the best photo watermark software for you to add text/image watermark. This image protection solution provides batch watermarking mode and enables to set photo frame, resize photo, crop picture and batch rename photos.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Batch Image Watermarker - Add stylish static or dynamic text and graphic watermarks to your images and photos.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
TSR Watermark Image - Protect your images online.
JPEGView - JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images.