In 1996, Glamour Shots was seeing $100 million in sales and had 6,000 employees, according to estimates from The Wall Street Journal and The Oklahoman at the time.

But the brand was based on a fashion trend that had already crested. By the late ’90s, said Jimmy Paul, a well-known hair stylist, grunge had gone mainstream, and looks shaped by Helmut Lange and Prada ushered in the minimalist era. “Makeup and hair got very stripped down,” he said. “It became about flat irons and straightening.”

While the portrait studio business overall remained stable — census figures showed modest growth in the industry from the late ’90s until the 2008 recession — many of the 350 Glamour Shots stores folded by the end of the 20th century, unable to escape their association with the outdated style.

“It just became passé,” said Bob Eveleth, the first Glamour Shots licensee and owner of nearly 50 stores at the company’s peak. “We did one focus group in North Carolina. One of the guys was talking about giving Glamour Shots gift certificates as a joke. And I thought we kind of crossed that threshold.” (Mr. Eveleth is doing fine.)

The remaining stores wilted in failing malls that charged steep rents. Then Apple and Samsung equipped every cellphone with a quality camera. About five years ago, with 30 to 40 stores left, a popular Groupon promotion provided a fleeting burst of new customers before technology almost completely wiped out Glamour Shots altogether.

Mr. Eng, the owner of the two remaining New Jersey locations, was the go-to guy for Glamour Shots modernization in the early 2000s. He traveled all over the country, advising stores to ditch the old wardrobes, offer boudoir sessions and business headshots, take full-body photos and emphasize a more luxurious, more expensive spa experience. The average sale at his stores is around $500, compared to $100 for typical stores in the ’90s. The high prices are the only way for Mr. Eng to cover his $12,000-and-up monthly rents, which he said he was currently trying to negotiate down.