Many companies use this software for editing photos.
I use this for our company work and this works perfectly for image editing process.
GIMP - GIMP is a multiplatform photo manipulation tool.
digiKam - Professional Photo Management with the Power of Open Source
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively 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!
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.