Every week, Euell Nielsen sets out on her mountain bike on what might strike some as a macabre mission.
She pedals through the gates of a cemetery, selects a section of graves, takes out her camera, and snaps a picture of every tombstone she passes, row upon row upon row.
As a contributor to the website Findagrave.com, Nielsen, of Lansdowne, is one of thousands of volunteers who are preserving images of headstones worldwide, expanding a digital repository that reportedly already holds 100 million photographs.
"This is family history, world history, and preservation," said Nielsen, 42, a church archivist and historical reenactor. "In 30 years, someone might steal a stone, or the weather may diminish it, but the internet never goes away."
In little more than two decades, Findagrave has accumulated not only the gargantuan gallery of headstones, but also 150 million grave records. These include cemetery and burial listings with birth and death dates and, if available, biographical information and photos of the deceased — all of which the volunteers upload to create online indexes and individual memorial pages for dearly departed total strangers.
The site's contributors range from working moms who squeeze their cemetery shoots in on weekends, to genealogy buffs undeterred by winter's bite or summer's burn, to Boy Scouts working on merit badges. They use digital cameras and cellphone apps that tag photos with the graves' GPS coordinates.
They have referred to their labors as "genealogical kindness," of particular service to people researching family trees. Requests for headstone hunts gladly accepted, no charge.
"You are connecting people to their past," said Russ Dodge, 46, of Conshohocken, a senior curator with the site. " ... And the past is a building block to who you are."
Jim Tipton, a Salt Lake City aficionado of celebrity resting places, started Findagrave in 1995. In 2013, it was purchased by Ancestry.com, a Utah-based network of genealogical websites with an aggregate of 17 billion historical records.
Findagrave isn't the only enterprise dispatching legions of volunteers to cemeteries to photograph headstones or transcribe information from them for online posting. Billiongraves.com, owned by a firm that creates genealogical research technology, boasts 120 million records. Interment.net lays claim to more than 6 million.
Access to the sites is free. Revenue is generated from advertising that appears on memorial pages, and various fees may be charged to keep pages ad free.
Internet-immortality ventures, however, are not without controversy, often centering on privacy issues.
Laws pertaining to cemeteries tend to be old and unclear, said Tanya Marsh, a Wake Forest University professor who teaches courses on the subject and authored the book, The Law of Human Remains.
"A lot of cemeteries have signs that say you can't take photographs and publish them without consent of the cemetery," she said. "That's interesting, considering that as a rule, cemeteries don't own the headstones. Next of kin own them."
Criminal statutes protect graves from disturbance or desecration, but not from being photographed, said Marsh. "The simple fact that we own it doesn't mean that we can prevent people from taking a picture and publishing it."
Still, websites field complaints from relatives who object to the information posted, or do not want the deceased memorialized in cyberspace at all.
Findagrave has an F rating with the Better Business Bureau, the lowest grade, because the site failed to respond to four of the 17 such complaints lodged against it from 2013 to 2016, said Patricia Driggs, president of the Utah bureau. The remaining 13 were addressed.
The A+-rated Ancestry.com has contacted the bureau about clearing up the outstanding complaints, said Driggs.
When disputes arise, Findagrave follows a "family first" policy, said Dodge, the curator. The site will remove a listing or allow information to be changed when the request comes from a close relative. Billiongraves.com will strip out a listing if a close relative asks, said Hudson Gunn, its president and chief operating officer. Interment.net also will eliminate information, though each request is evaluated on its merit, said publisher Steve Johnson.
Website volunteers often function as headstone detectives for people trying to pinpoint family members' resting places.
Last month, Pam Gleason, a volunteer from Edgewater Park, was looking for the grave of her own uncle, in Sunset Memorial Park in Coos Bay, Ore. She emailed a photo request, and a volunteer living near the cemetery found the plot, snapped a picture, and uploaded it within a week.
"We had no idea he had been awarded the Purple Heart, and we never would have known if we hadn't seen a picture," said Gleason, who has photographed grave markers at Beverly National Cemetery in New Jersey.
Jennifer O'Donnell, a college web manager, has worked on a photo archive of Arlington Cemetery near her Drexel Hill home for a few years. So far, she has uploaded 53,000 images, nearly 50 percent of the graves there.
Tom Myers, of Holmdel, N.J. has posted 175,000 photos from 105 cemeteries in Southeastern Pennsylvania since 2010. An actuary who has been involved in genealogy for 30 years, Meyers is among the site's top 50 photographers.
He spends one day a month in a cemetery, "mowing the rows," as the volunteers call it. He takes as many as 3,000 shots in eight hours.
Findagrave instructs volunteers to be respectful and obey cemetery rules. They are not supposed to alter stones or clean them, beyond wiping away dirt with a soft brush or a cloth moistened with water.
Dana Smith, 33, shoots photos on weekends at Highland Memorial Park near her home in Pottstown. An administrator at a trucking firm, she also photographed two cemeteries while on vacation in Dublin, Ireland. And she has taken on 162 email requests, which she tackled with her pal, Jen Brown.
"We treat it like a [cemetery] hunt," Smith said. "[Brown] goes one way, and I go another.
Every year, Smith attends Findagrave's Community Day, when the site urges volunteers to gather to clean local graveyards.
"It's really different to meet people who frequent cemeteries as much as you," Smith said. "You don't feel as weird."