Black Swan:

The image used features the main Protagonist in the film. It takes up alot of the page by being placed in a very central position this indicates that the story is focused on this character.
The formal elegant style of the font against the contrasting background conforms to the thriller genre: drama, this mirrors a possible dark and intense storyline.
This film poster uses dark colors in the background to match with the title “black swan.” Also, Natalie Portman is displayed in light colours signifying that she is the ‘Light in the darkness. The crack down her face may exemplify the downfall or destruction of her good side.
Inside that cracks it looks as though black feathers are underneath (black swan). In her hair there is a white feather, this can characterise the ‘pure’ swan as white has associations to purity.
The black demonstrates contrasts with the bright pale complexion of her skin makes it appear bolder. The quote in white gives a unique twist that creates suspense with the word ‘intoxicating’.
The actors and actresses’ names are written in a line across the poster and their second names are in the bigger font. At the bottom it says ‘fox searchlight pictures presents’ in conventional font of a poster, to advertise the company responsible for the production.
Psycho:

Using bright vivid colors to engage the audience and to reflect the sub genre psychological thriller, as well as red are used to gain our, attention to specific character in the poster. Also, the black and blue colours juxtapose with the subtle yellow with reds used, they complement one other to effectively depict the thriller genre.
The title is ‘Psycho’ which connotes danger and anger as well as the style it is written in with a sharp line across the word which separates the top part from the bottom, this gives the observers a feel that there is a psycho in the movie.
Both the title and the woman (Marion crane) who is played by Janet Leigh are in yellow, this could allude to a link between both of them.
The darker colours, signify death and destruction, whereas the pulsating red and yellows are associated with danger/warning.
All images have a black background reflecting dark undertones for the film, therefore creating a mysterious/evil menacing, appeal to the audience. And leaving the viewer wondering what mystery is laying around which builds great expectation to watch the film.