I've been thinking a lot about the use of images ever since I attended a talk on revelation dreams by a writer. He spoke of how metaphors work or don't work. They don't work when they are superimposed on the words. Rather, for them to be effective and powerful, the words should attach to the image.
And this is easier to do with film.
In Atonement the image of water repeated over and over. A pot chip in a fountain, a girl in a fountain, a man in a tub, a hand on the surface of water as if to still it (or still the emotions within), a child recklessly jumping into a waterfall. And then there's the sea - as a means of escape from Dunkirk, the sea as a dream or a smell, the sea as a place of retreat. Then there's the powerful image of a mother washing her son's feet. Powerful to me because of its religious evocation and the message of redemption and humility and love. And the horrifying image of water rushing into a London tube station.
And then there's the tears - tears of longing, tears of horror, tears of fright, tears of guilt. So many emotions qualifying human tears.
Water is there but unable to be grasped. Likewise, in the story, reality is there but unable to be grasped.
Some reviewers thought the movie too heavy handed with the images, referring to the images of horror and war. They argued that one picture conveys enough horror - that the viewer doesn't need as many as are offered. Perhaps that's a fair critique of the film. But the darkness, for me, matched theme of the story and of storytelling. And that storytelling improves that darkness.