This is because the photos seemed to be based on our world, and not the world of Monster Hunter which caused some concern about how the film will turn out. However the good news is that the movie is expected to feature characters and monsters from the game, according to Anderson’s interview with /Film (via DualShockers).
According to Anderson, “No, the movie has a lot of characters from the video game in it. There’s The Handler and Admiral, Aiden, Aiden’s Handler. We wanted Palico. It’s very much a movie of the video game, but in Monster Hunter you get to create your own character when you go in there. You don’t get to play Lara Craft or Jill Valentine. You get to play your own creation, and there is definitely an element of that in there.”
He adds, “So I think for fans of Monster Hunter World, you’ll recognize that world and the characters from that world very much, but also it’ll be a callback to some of the favorite moments and creatures from some of the earlier games.” That being said, video game movie adaptations have typically done rather badly, so it remains to be seen if Monster Hunter will be able to break that curse.