This picture represented a very brief time when Fox wanted to create their own cinematic universe using the Marvel properties they controlled, so that X-Men and Fantastic Four would cross over. They actually hyped this for a bit, hence why they took a picture of the combined casts for publicity.
Then Fant4stic came out and it was absolutely trash and the entire idea was abandoned. Also there's Channing Tatum representing the Gambit movie that never got off the ground and probably won't now that Disney bought out Fox.
Also the Fox X-Men series is conclusively ending as the X-Men series is getting rebooted in a few years at Disney, so basically no part of this planned cinematic universe is going to survive.