It might be easy to take them for granted sometimes, but posters can play a large role in both a film's marketing before release, and a film's status—iconic or otherwise—after release. A great poster doesn't always equal a great movie, and there are plenty of very good movies that have forgettable posters. But some posters go above and beyond, and really stand out from the crowd, and it is admittedly often the case that being tied to a classic movie helps the poster (and vice versa).