Many companies use this software for editing photos.
I use this for our company work and this works perfectly for image editing process.
Pennywise - Cross-platform application to open any website or media in a floating window
GIMP - GIMP is a multiplatform photo manipulation tool.
PiP for Mac - Always on top window preview similar to the popular windows only OnTopReplica
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.
PiPer - A DIY Minecraft computer to build gadgets
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.