It’s the smile that catches you — that jet-set smile covered in frosted lipstick, behind those morning-after-the-party shades. In the photo, taken in Paris, Pippa Middleton sits in the red leather seat of a black convertible, smiling as the driver of the car points what appears to be a semiautomatic pistol at the lens.

Snap. In that instant, Middleton, the partying little-sister-in-law of Prince William, best known for her curve-hugging bridesmaid’s gown, joined an entourage of celebrities who have been caught in “gun situations.” The list is long — actors, ballplayers, rappers, politicians: T.I., Lil’ Wayne, Gilbert Arenas, Eminem, Dick Cheney, Puff Daddy and Jenny from the Block.

The photograph plays on many stereotypes. Is the royal in-law now an outlaw, irretrievably linked with the bad crowd? Or will her associations with a fairy-tale wedding and with Princess Diana’s attempt to flee paparazzi in Paris allow her to escape such categorization?

“We see the face of the guy holding the gun,” said Robert Thompson, professor of popular culture at Syracuse University. “All we see is his right eye, and it does look menacing. When you get some context to the photograph, you see that the gun — whether it is real — is aimed at the paparazzi. That gives it a narrative. And, of course, Princess Diana is at the center of that narrative. People remember the paparazzi chasing Dodi [al-Fayed] and Diana the night she was killed.”

The photo frames cultural contradictions. Celebrities “may hate the paparazzi,” Thompson said. “On the other hand, the paparazzi are part of the machine that makes them famous.”

And the public depends on the paparazzi to feed its appetite for celebrity news. “We want to see the pictures in Us Weekly, in People magazine and OK magazine,” Thompson said. “There is this dysfunctional relationship between the paparazzi and us.”

Details of what happened in that car are still emerging. According to reports, Middleton and the driver — identified in Us Weekly as Romain Rabillard, 36, a lawyer known to hang out with Paris’s chic crowd — were questioned by city police. No charges have been filed.

Paul Harrison, royal correspondent for Sky News in London, told a television reporter that Paris police are investigating the incident, a potential crime in France that could bring a two-year sentence if the gun was a toy and seven years if it was real.

“St. James’s Palace is not saying anything” because Middleton is not a member of the royal family, Harrison said.

“When you reach a certain level of celebrity, it should be obvious to you or your team that being around guns is a pretty dicey thing,” said Jim Bates, a member of Sitrick and Company, a Los Angeles-based firm that handles crisis management for celebrities. “Being around guns in a loose way and in a casual way is an invitation for disaster for your image.”

Middleton has reportedly not made a public comment on the incident. But experts who often advise celebrities caught in sticky situations would advise her to get her side of the story out quickly.

“It would be a good idea to express remorse,” Bates said, “and say it does not convey who she is, and then in the future make sure she stays away from incidents like this one.”

Allan Mayer, principal partner of 42West, a public relations firm based in Los Angeles and New York, said: “People like to think of crisis management as this dark art used to solve a problem. . . . When a client does something wrong and is unwilling to own up to that act, there is nothing that can be done.”

Middleton could easily play on the sympathy of her fans. “When you think about a royal being pursued in a car, people remember what happened to Princess Diana,” Mayer said. “And one could say, ‘I’m not surprised one driving her in the car might be moved to some response.’ ”

On the other hand, Mayer added, “If she appears to be laughing and enjoying herself in the picture, that would make it more difficult to make that connection.”

The last in the series of photos shows Middleton and her friends driving away. Through the windshield, they look jovial.