Hollywood can’t seem to help itself sometimes, and even though everyone knows what an actor looks like, the studio will approve a little digital retouching without asking first. For very good reasons, Keira Knightley was aghast when it happened to her. Common sense suggests that stars sell movies, and if the stars aren’t the main driving force, then it’ll be the concept. If not, a familiar title or a recognisable brand will do the trick, but in …