digiKam - Professional Photo Management with the Power of Open Source
Sketch - Professional digital design for Mac.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Photos on macOS - Photos keeps your images organized and accessible. Rediscover favorite shots with Memories. Access them on your devices with iCloud Photos.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.