A Google spokeswoman said anyone could request a Sphere image be removed. Ms. Harrison said she had no intention to do so, though she also said she would have turned Google down had the company asked to photograph the park.

Since it opened in 1831, Gramercy Park has been off limits to anyone but those living on the border of the two-acre greensward and their guests. Such luminaries and dignitaries as Vincent Astor; James Harper, the mayor and publisher; the Steinways; and Thomas Edison moved in, each receiving a key made of gold. Those have been replaced by special nickel-alloy keys specially made in Virginia, and they can now be found in the hands of Uma Thurman, Rufus Wainwright and, until he sold his apartment last year, Karl Lagerfeld, Chanel’s creative director.

Like many of the rules within the park — no pets, no Frisbees, no smoking — the one banning photography, specifically commercial photography, is bound up by tradition as much as reason. “The park is for pleasant enjoyment,” Ms. Harrison said. Until 2010, wedding photographs were allowed, but now anything beyond a personal photo for the mantel is forbidden.

Small signs in the flower beds at the north and south entrances show a few of the rules, with dogs, cigarettes, cameras and the like x-ed out, but there are no other warnings posted. Under most circumstances, none are needed.

“There are people watching the park at all times,” Ms. Harrison said, sitting inside the small shed and holding the clipboard she carries with her at all times. “If something happens, if they see a camera or a ball, you better believe I’m getting a call about it.” (While she allowed a reporter into the park, a photographer was asked to remain outside during the interview.)

Phyllis Herman, a key holder who lives on the north side of the park, was, like most of her neighbors, unfazed by the photos online. “I don’t consider it a violation, no,” she said. “All we do in there is sit around anyway, so a few people gawking online won’t change that.”