Many companies use this software for editing photos.
I use this for our company work and this works perfectly for image editing process.
AndreaMosaic - With AndreaMosaic you can create your own photographic mosaics made with your own pictures.
GIMP - GIMP is a multiplatform photo manipulation tool.
WidsMob Montage - Make stunning mosaic photos or montage shape with tiles, which supports both JPEG and PNG files.
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.
Mosaic Creator - Mosaic Creator is professional mosaic tool. You can create your own picture mosaic.
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.