SHANGHAI, June 24 (Xinhua) -- Sunlight filtered through an old wooden window, catching the silver wisps of an elderly woman's hair as she nervously straightened the hem of her clothes and brushed back strands at her temples. Then she looked into the camera and offered a shy, deliberate smile.

Behind the lens, 43-year-old Zheng Yu recognized the significance of the moment -- it might have been his subject's first proper portrait, perhaps, even, her last.

In Shanghai's lesser-seen corners where smartphone cameras seldom linger, the retired soldier-turned volunteer photographer has documented more than 20,000 such moments since 2013.

Zheng enlisted in the military in 2000. Five years later, he was back home, working as a community videographer. Though he retired from service, Zheng continued his commitment to public service, just without the uniform.

He swapped his rifle for a camera. The mission didn't change.

His project began unexpectedly, during a routine shoot in a local community. "Are you taking photos or videos? I'd like a picture to leave for my grandchildren," an octogenarian woman asked.

Zheng was not able to fulfill the woman's request as he was filming at the time, yet her request stayed with him. Even in this glittering metropolis, he realized, many elderly residents had never sat for a portrait, alone or with their families. That single encounter prompted Zheng to begin offering free portraits to elderly residents in local communities.

On his first visit to Qixian Village in Shanghai's Fengxian District, only a handful agreed to participate, while most were wary of hidden charges. But when he returned days later with printed photos, the response was warm and emotional.

"They smiled like blooming flowers," Zheng recalled. One resident who had initially declined expressed regret. Zheng promised to return.

The next time, he found benches already lined up in anticipation. That afternoon, more than forty pairs of hands, some stiff with age, lifted into unsteady V signs. Their smiles, tentative but unmistakable, filled Zheng's frame. "I realized then just how much this mattered to them," he said, resolved to continue.

Some encounters left a deeper mark. One old woman requested a plain white background, explaining that the photo was for her memorial. At a nursing home, another carefully dressed in a bright red coat for her portrait, saying it was for her family to remember her by. She passed away shortly after, prompting Zheng to purchase portable printers with his own savings so that no one would have to wait for their photo again.

The photos took on unexpected meaning. When Zheng returned to visit families in 2017, he noticed how the portraits he had taken two years earlier had been carefully preserved. Some were wrapped in layers of plastic, others placed beneath glass tabletops. One man kept his photo under the bed, stored with burial clothes in a "memory box."

Moved by these stories, Zheng launched the "Love Frames" initiative, encouraging the public to donate photo frames so that seniors could protect and display their portraits with dignity.

Zheng's path in volunteer photography since 2013 began with three volunteers, including himself, and has since grown into a citywide effort. In 2016, as the team expanded to ten, Zheng named it Shi Guang, or "Collecting Time," reflecting its mission to capture and preserve fleeting moments of everyday life.

Media coverage drew wider attention, bringing in volunteers from across professions, including civil servants, journalists, entrepreneurs and students. Caring businesses followed, with one company donating 14,000 photo frames.

Over the past 12 years, more than 4,000 volunteers have taken part, providing portraits for over 20,000 seniors and printing more than 23,000 photos. They've also delivered seasonal aid to over 8,000 sanitation workers, delivery men, and others who work outdoors.

Today, the team operates out of a small modular unit known as the "Apple Cabin," a container-style prefab structure, in Shanghai's Bubble Park. The small studio, equipped with a refrigerator and air conditioning donated by local supporters, serves as their permanent base.

Zheng hopes more people will join the cause, offering time, resources, or simply compassion. For him, it remains a continuation of a vow he made years ago.

"I promised that even without the uniform, I would continue to serve the people," he said. "This is how I keep that promise."