The Rise of the Auto Paparazzi.

Brenda Priddy regularly battles extreme weather and squirrely automakers to photograph new cars while they're still in development. But sometimes she just gets lucky, like when she recently spotted a 2007 Ford Edge SUV that was getting tested near her Arizona home. She immediately drove after it. "I don't get involved in chases," Priddy says, "but we got a lot of pictures as the Car was speeding away from us."

Welcome to the world of car-spy photographers, who are to Detroit what celebrity shutterbugs are to Hollywood. Auto paparazzi can sell shots of an especially noteworthy car to magazines for up to several thousand dollars, an incentive that often leads to desperate measures. Jim Dunne, who arguably invented the niche market in the Sixties, allegedly once rented a helicopter to view a new Corvette he couldn't capture on the ground. Other photographers lurk outside test tracks, enduring 120-degree heat in Death Valley (where cars undergo hot-weather testing) or subzero winters in Sweden (for cold-weather testing).

Priddy, the doyenne of spy photographers for thirteen years, says it takes a practiced eye to spot so-called test mules. Prototypes are concealed with tape or vinyl or even camouflaged with fiberglass panels of another carmaker. "The first disguise for the VW Touareg was a Mercedes M-Class body," Priddy recalls. "I happened to be with a VW buff who looked underneath and said, 'That's no Mercedes.'"

"I tend to think of it as a cat-and-mouse game," says Ford spokeswoman Jennifer Flake of car-spy photos. Priddy's success at outsmarting carmakers has led to recent "gets" such as exclusive shots of the redesigned Honda Civic and the Bugatti Veyron. "The ones that draw heat are the real sexy stuff â€" the Ferraris and Porsches," says Motor Trend's Matt Stone, whose magazine runs at least four spy shots every issue. "Nobody gets choked up over what a new minivan looks like."