The Forbidden City, Beijing, China. September 7, 2007.

PARIS — There is a civil contract implied by photographs. An Israeli writer, Ariella Azoulay, published a book making that point. Henri Cartier-Bresson made it too. He described shooting pictures of people as a “sort of violation,” adding, “if sensitivity is lacking, there can be something barbaric about it.” There can be, of course, and not just when the subject doesn’t like the image.

We, viewing the pictures, are complicit. As consumers of images we bear witness through them. Or we’re voyeurs. In either case we complete a transaction that we instigated, in that a photograph is made hoping someone will look at it. It’s a message tossed into the ocean of time, and how we read that message, whether indifferently or with compassion, can have moral dimensions.

Excerpted from ‘When a Picture Is Worth a Thousand Debates, Give or Take,’ by Michael Kimmelman. Published June 3, 2009, in The New York Times.