digiKam - Professional Photo Management with the Power of Open Source

ACDSee - ACDSee is an image viewer that uses very little system resources, and it has a small, sleek size that won't take up much space on your system.

Photos on macOS - Photos keeps your images organized and accessible. Rediscover favorite shots with Memories. Access them on your devices with iCloud Photos.

Photoscape - high quality photo editing software, that enables you to fix and enhance photos.

XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!

Fotor - Fotor is an all in one visual platform. It includes photo editor, collage maker, and graphic designer. You are free to make a visual look more beautiful.