Good idea re saying which film/TV show the stills are from - i'll put that to the design team.
Re choice of images - we have access to picture libraries for all the new and upcoming film/TV releases and our designers choose the best shots.
In an ideal world (and it occasionally happens!) we find a film that's a massive blockbuster hit AND that we have access to the, say, 10 superb shots we need across a TV supertest plus the front cover of the mag. More often than not we're limited to a handful (if that) of decent stills, and we'll use them in First Tests and elsewhere.
You'd be amazed how frustrating/hard it can be to get the perfect shot from the best film - film PRs sometimes just don't *get* it!
And they're not meant to be pictures of the sets in action, really - they're just far more interesting to look at than a blank screen!