Jon Landau was gave the folks captured in the set photo, including Second Unit director Garrett Warren and stunt performer Steve Brown. With a production as massive as the Avatar sequels, there are tons of artists collaborating to turn the vision into a reality. And the Second Unit director in has a ton of responsibility, especially since two movies are being filmed at once.
Avatar fans can re-watch the original movie on Disney+. You can use this link to sign up for the streaming service.