It says something about our eyeball-dominated era that it’s hard to imagine anyone bothering to write analyses about the power of photography. Images are irretrievably threaded through our culture; we’re a society that sees more than it reads. But then, why else might On Photography: A Tribute to Susan Sontag, a thought-provoking exhibit at the Metropolitan Museum of Art, be a cold-water dowse in prickly heat?

Forty photographs in two rooms are juxtaposed with some of Sontag’s eye-opening observations about photography, many first published in the New York Review of Books, then anthologized in 1977’s On Photography, then revisited in her final published work, 2003’s Regarding the Pain of Others. There’s a good deal of work by many good names: a Napoleon Sarony image of Oscar Wilde; an Andy Warhol photo-booth self-portrait; a Julia Margaret Cameron capture of Lord Tennyson; a Diane Arbus print called, with not a little irony, “Boy with a Straw Hat, Button, and Flag in a Pro-War Parade, N.Y.C.” But the images only fully activate when reading some of the succinct Sontag snippets nearby.

Of two August Sander 1920s images—a high school student, an unemployed German sailor—Sontag acutely and cruelly observes how “a cretin is photographed in exactly the same dispassionate way as a bricklayer.” Beside Peter Hujar’s famous shot of Sontag on a bed is a credo: “Seen through photographs, people become icons of themselves.”

Good of her to notice. Good of her, also, to see a measure of seriousness in absurdity. Take two classic photographs by Edward Weston, for example: a 1934 nude and a 1930 pepper. His pepper images were, of course, one reason why Weston was so celebrated, but the result of the juxtaposition, she writes, “is a discovery of the erotic suggestiveness of an ostensibly neutral form.”

The grinning and earnest pro-war demonstrator seen in the Arbus image awakens us, of course, to Sontag’s vaunted liberalism; a disquieting Walt Cisco shot of the Kennedys in the Dallas motorcade does, too. But don’t let politics overshadow some of Sontag’s keenest insights. An image of a Russian Dowager Empress isn’t merely part of a travel album, it’s the occasion to think about how and why “tourists feel compelled to put the camera between themselves and whatever is remarkable that they encounter.” And a riff on “fascist dramaturgy” beside an arresting Leni Riefenstahl photo proves, politics aside, that the power of Sontag’s public face was matched by her eyes.

Through September 4. Metropolitan Museum of Art, 1000 5th Ave. (at 82nd St.), 212-879-5500;

$20 suggestion donation.