The images, which showcase Marcus' keen sense of style, are featured in a new book compiled by his daughter and granddaughter and at an exhibit at the Dallas Museum of Art.
"We knew he had great taste," said William Keyse Rudolph, who curated the museum exhibit, which opened in January and continues through March 30. "What we didn't know was that he was making art."
The images offer a glimpse into the life of the man whose family founded luxury retailer Neiman Marcus, a company where he had a nearly 50-year career.
One shot from 1965 shows Marcus' son Richard fishing off the coast of Acapulco, Mexico. A straw hat and dark sunglasses shading his eyes, he is clad in a light-blue shirt and white pants as the ocean glistens behind him. In another from the 1950s, designer Emilio Pucci films Marcus as the retailer photographs him in Florence, Italy.
"These aren't just family snapshots," Rudolph said. "This is a man and his world."
The photos are significant not only for their sometimes famous subject matter or depictions of a certain 1950s and 1960s cool, but also for their composition, Rudolph said.
"He really wasn't dabbling," he said. "He certainly took his work seriously."
One photo captures fashion photographer Elsbeth Juda leaning forward to view Mexico's Teotihuacan Pyramids in 1957. "Her body is echoing the pyramids," Rudolph said. "He waited for the right moment."
It was a moment about 10 years ago that the fate of the photos was decided. Marcus called up his granddaughter, Allison V. Smith, to ask if she wanted his slides.
"He told me that if I didn't take them, that they would go in the trash," said Smith, a professional photographer. "I said sure I'd take them."
What he deposited with her were about 5,000 Kodachrome slides, perfectly organized in leather boxes with drawers, some still bearing Neiman Marcus' 49-cent price tags.
Smith didn't have time to sort through the images before storing them in a closet. A couple of years after Marcus' 2002 death at the age of 96, she took a closer look at the slides and began posting them on a photo-sharing site.
With no mention of Stanley Marcus or Neiman Marcus, she simply labeled them "Kodachrome vintage slides." Within about six months, the photos had received more than 10,000 views and glowing comments, Smith said.
As Neiman Marcus began preparations for its 100th anniversary, Smith and her mother, Jerrie Marcus Smith, decided to publish a book of the photos. The book, "Reflection of a Man: The Photographs of Stanley Marcus," was released exclusively to Neiman Marcus last fall and is set for wide release in February.
The book features 192 images from 1936 to 1971, while the museum features 39 photos, mostly from the 1950s and 1960s.
"It has been so much fun following his trail through the media he used," said Allison Smith, who noted that her grandfather also made home movies and was an inveterate letter-writer.
Jerrie Marcus Smith said her father always had a camera around his neck or in his pocket and often gave friends photos he took of them.
Rudolph said that Marcus was deeply interested in art, serving as a trustee of the museum for more than 60 years and donating more than 300 works to the museum.
What is immediately striking as one looks at the images is the colors, for example, a snapshot of Marcus' wife and a group of friends all clad in colorful outfits framed against a blue water.
"There's this gloriously deep, rich saturation of colors," Rudolph said.
Rudolph said that many people are responding to the colors and the fashion in the images. They're also enjoying the scenes captured, including gatherings of family and friends: "You feel like these people were having the most fun," Rudolph said.
"It's really captivating people on a variety of different levels," he said.