Canadian photographer Diana Shearwood has been known to pull a quick U-turn on a busy highway in the service of art.

The Quebec artist photographs the oversized food images spread across the holds of trucks, especially the big rigs that do the long-distance schlepping of our groceries.

A glazed doughnut the size of a hot tub beckoned as it passed through St-Michel, Quebec. A huge halved orange glistened like the summer sun in the company of other enlarged fruits and vegetables on Highway 495 in Massachusetts.

They landed among 86 of Ms. Shearwood's color inkjet prints -- eight of them presented in large-format plus a grid of 78 others -- that comprise the engaging exhibition "What's for Dinner? Photographs by Diana Shearwood" at Silver Eye Center for Photography.

Infrequently, her subject comes to her, as on the morning an SUV-sized delivery truck covered in olives, salami and garlic stopped in her neighborhood. "Coffee fuels me. I hadn't had my coffee, and it was raining. I pulled my raincoat over my pajamas, I ran out, and [she makes the sound of a shutter]."

She's also had luck in parking lots. In fact, the Canadian title of the exhibition is "Behind the Mall," a reference to the fact that the big trucks park in back of Canadian malls, unlike in the United States, which necessitated the exhibit's name change here.

Ms. Shearwood, who is known for her photographs of urban decay and abandoned buildings, was first attracted to the truck images because the good ones are such technical achievements. "I'm not by any means poking fun at it," she says. "I admire the photographers who make these incredibly effective images."

She says she didn't choose food as a topic intentionally; things came together that way. Food had been part of her overall concern with environmental issues while in school in the 1970s, but "it went out of my head. And then I started thinking about food again, and about eating well.

"I've always been interested in technology. The quality of printing for that size -- I find that astounding."

Ms. Shearwood began Web searching "vehicle wrapping" and "fleet graphics," as the product is called, to see how it is done and by whom, and soon she was reading about sustainability and eating local.

"My only fear is that it sounds like I'm proselytizing, I'm preaching. And I'm not. I'm asking people to think about it."

One decision Ms. Shearwood has to make is whether to photograph the food image alone, or the entire truck within its environment. Each has an advantage.

Isolated, the food images contain an element of surprise that's revealed when examined closely, as when viewers stumble across the truck's handle embedded among the red-orange-yellow line-up of vitamin drinks found in L.A. And, of course, the aesthetic is more still life than landscape.

But taken within a larger context, they become another creature, often making cultural commentary.

A rice burger speaks to viewers in Hong Kong, while a colorful, moist-looking fish fills the frame in Portland.

Sometimes the critique is, if inadvertently, political, as with the American flag that waves in the breeze against a vivid blue sky behind a huge, succulent, grilled steak.

Ms. Shearwood also debated whether to include images with people in them, but soon decided they were part of the story. They also often, intended or not, add to the humorous quality of the work that appeals to her.

"Look at this guy," she says, pointing to a blown-up figure sporting a red apron and come-hither look, lounging across the back of a truck. If he's the prize for eating the food depicted, it's not much incentive, she observes.

"And then, of course, we have our p.c. children," a diverse mix of happy faces. "And then we have sex. I call her the Grapefruit Girl," she says of the bikini-wrapped upper torso of a headless woman who is suggestively posed next to a giant bottle of pink grapefruit juice.

Another element that comes through in Ms. Shearwood's current work is the pervasiveness of ads. While she says she "didn't really make the project about advertising, I think about advertising -- how we're so immune to its ubiquitous nature."

Whether it's a pretty, smiling young woman holding a container of yogurt in a Shanghai ad; a plate of sausages steaming on a panel in Dingle, Ireland; or a woman wearing a veil walking in front of a painted truck in Marrakech, Morocco -- the cultural implications are similar: Food has shifted from a home-grown necessity to a commodity delivered, and packaged, by the marketplace.

"A point I wanted to make is that the problem is not specific to the U.S. Not even to North America."