Hi. Can you tell me how this is done? Is it difficult? What software do they use? I want to do this with images rather than videos.

It looks so real.

The Corridor team have been in the CG/FX business for a while. Besides Chappie-style videos, they have also been AI-faking celebrities. They have demonstrated to the world how Disney-Marvel-Lucasfilm's de-aging CG sucks, and AI de-aging is the way to go. You need quite a few years of 3D CG training and advanced hardware (graphics cards) to do half of the work these guys are doing. Most people can't handle this kind of workload, unless they are extremely motivated and talented.