Photographer Traer Scott was looking through digital snapshots she had taken of dogs at two Providence shelters when she realized that most of her furry subjects had been euthanized.

She felt chills up and down her spine.

“Those pictures were the only record of them having been here. If I deleted them, they were gone forever.”

Scott, 33, had been volunteering at the shelters, helping staff take photos of the canine residents to post on the shelters’ Web sites in hopes of finding the dogs new homes. Both shelters euthanize dogs that are deemed unadoptable because of aggressive behavior or are terminally ill.

“I couldn’t bring myself to get rid of their photographs,” Scott said. That’s when she had a brainstorm: She decided not to just take snapshots, but to use her skills as a professional portrait photographer to capture the personality and individuality of each dog. She hoped a strong portrait could give a dog a better chance of being adopted.

“A clear, expressive picture will catch someone’s attention when looking through the thousands of photos,” noted Scott, who lives on the East Side of Providence with her husband, Jesse, and two dogs, 11-year-old border collie Cricket and 5-year-old pit bull Audrey. Both pets were rescued from dire situations.

The resulting emotional pictures of “man’s best friend” also caught the attention of a publisher, Merrell Publishers. The company, based in New York and London, and which specializes in art and illustration books, helped Scott turn the portraits into a coffee-table book called Shelter Dogs, which was released this fall.

In her book, Scott captures respect, dignity, uniqueness, and humor. She shows that despite less than optimal living conditions, the dogs manage to shine. Her pages feature big, little, mellow, adorable, loving, frenetic dogs of many mixes.

The pages introduce a cast of lovable canines such as Celeste, a Siberian husky that Scott described in her book as “frenetically hyper. My camera captured a fleeting moment of repose that lasted less than five seconds.” Her subjects have names such as Bunker, Cocker, Timmy, Fluffy and Ox. She wrote that Ox, a bulldog, “was a class clown. His comical mug matched his charming personality.”

About 7.5 million animals are ready for adoption in more than 6,000 shelters in the United States. At Providence Animal Control, a shelter run by the city and one of the two where Scott made her portraits, director Peter M. Brown estimated that about 700 dogs were picked up off the streets last year. About two-thirds were either returned to owners or adopted. About one-third were deemed too sickly, vicious or unsocialized to be adopted.

Similarly, in 2004, the private, nonprofit Providence Animal Rescue League, whose subjects Scott also photographed, found homes for just about 500 of the nearly 840 dogs received. About 132 were returned to an owner; 191 were unadoptable and euthanized.

The majority of the nearly 60 dogs photographed in Scott’s book, which sells for $19.95, ended up finding homes. Only a few were euthanized.

THE BOOK HAPPENED almost by accident. In July 2004, Joan Louise Brookbank, a director at Merrell Publishers, was reviewing Scott’s portfolio at a meeting of publishers and photographers in Santa Fe.

“Her work reminded me of European photography from the ’30s and ’40s,” she said. “I liked what I saw, and then asked if there was anything else I hadn’t seen.”

Scott had brought only a few of the shelter dogs’ photos, but Brookbank said she was hooked.

“I couldn’t get the images out of my mind” she said. “I showed the pictures to the sales force, and everyone agreed we had to publish them.”

The initial printing was to have been about 10,000. But after Shelter Dogs was previewed to booksellers, they decided to triple the order.

It was also decided that the book — filled with “passionate passages written by Scott,” added Brookbank — needed to be tied to something meaningful. Fifty cents of each sale goes to the American Society for the Prevention of Cruelty to Animals.

“This book is a great way to see beautiful fine photography,” she said. “It also encourages people to adopt animals from shelters and sheds light on the conditions in shelters.”

WHEN ED SAYRES, the president of the New York City-based ASPCA, found a copy of Scott’s Shelter Dogs in his work mailbox, he bought 35 copies immediately. He said he ordered them before he even knew the ASPCA was selling them at the office, and that a portion of each book sold would be donated to the organization, which is devoted to the humane treatment of all animals.

“I fell in love with the book,” he said. “I’ve seen many books on stray animals, and this one was just incredible because you could connect and empathize with the dogs.”

A 32-year veteran in the field of animal rescue, Sayres said the book puts a spotlight on the nation’s rescue system and the kinds of quality dogs you can find at shelters. He added that Shelter Dogs helps to underline the need for treating our four-legged friends humanely and compassionately.

Hollywood animal trainers long ago discovered the advantages of adopting dogs from shelters. About 80 percent of the animals that appear in films and on television have been rescued, reported the American Humane Association, which monitors the treatment of animals on film sets. Among those famous canines are Fang from Harry Potter and the Sorcerer’s Stone; Max in How the Grinch Stole Christmas; Lucky, who starred in Dr. Dolittle; and Eddie, the Jack Russell terrier who appeared in TV’s Frasier.

Photographer Traer Scott said that one thing she hopes to accomplish with Shelter Dogs is to “inspire people to adopt rather than buy. I want the word to get out that even if you want a purebred, every breed also has a rescue league.” Regular shelters end up with purebreds, too, she said.

SCOTT SAID SHE LEARNED to love animals from her mother, a curator at a natural history museum in Raleigh, N.C., who brought home a menagerie of rescued animals, from snakes and rabbits to squirrels and lizards. It was her mother, she said, who made her aware of animal shelters and the plight of cast-off and abused pets.

“While the other kids in my neighborhood trick-or-treated for UNICEF, I collected for ASPCA,” said Scott, an only child. “At age 13, I became a vegetarian.”

But for an animal lover such as Scott, volunteering at the Rescue League and Animal Control has had its trying moments. “It crushes me when I see an animal that comes into the shelter that has been beaten,” she said. “It’s very hard when you work with a dog one week and go back the next week and the dog is gone because it has been euthanized.”

She credited Katenna Jones, a co-volunteer at the animal shelter who is now an animal behaviorist and special agent at the Rhode Island SPCA in Riverside, with helping her overcome her initial apprehension about volunteering at a shelter. Scott said, “Katenna would say to me, ‘Okay, now it’s time to put the emotions aside because another dog needs your help.’ ”

Scott’s work with shelter dogs has become her passion, and she plans to continue photographing animals in need.

“I’m on a mission to encourage people to consider a shelter animal when choosing a pet,” she said. Shelter Dogs can only help.