Many companies use this software for editing photos.
I use this for our company work and this works perfectly for image editing process.
Aseprite - Aseprite is an art program dedicated to the creation of pixel art.
GIMP - GIMP is a multiplatform photo manipulation tool.
Pixel Art to CSS - Draw and animate pixel art, export the results to CSS
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.
Trixel - Instagram for triangular pixel art
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.