In case you were wondering, Netflix go to great lengths to select the most enticing preview image possible for you when you're presented with a list of possible viewing choices:
For many years, the main goal of the Netflix personalized recommendation system has been to get the right titles in front each of our members at the right time. With a catalog spanning thousands of titles and a diverse member base spanning over a hundred million accounts, recommending the titles that are just right for each member is crucial. But the job of recommendation does not end there. Why should you care about any particular title we recommend? What can we say about a new and unfamiliar title that will pique your interest? How do we convince you that a title is worth watching? Answering these questions is critical in helping our members discover great content, especially for unfamiliar titles. […]
My experience is that some of the time I already have an idea of the image I associate with a film and it just adds to my confusion if I see the same title being represented by a completely different image a few weeks or months later. Perhaps once I'm in their record as having watched a film, they should have a field which notes that and locks in the ID of whatever image was shown to me at the point when I viewed it.
[Via The Overspill]