Well that's awkward now isn't it. Either someone in this cinema in Shanghai is a major prankster and Loki and Thor shipper, or they really just didn't know what the movie was about and just picked an image for their Thor: The Dark World poster which showed the two male leads (which is imaginable because who doesn't love Tom Hiddleston). Whichever it was, the results are brilliant because this fan-made poster for the film is better than any other out there.
Who needs Natalie Portman anyway.