And although many workers appreciate the flexibility to schedule their own hours, they don’t have the same protections and benefits as full-time employees. Evidence suggests that the shift to on-demand labor may increase economic vulnerability for the roughly one-third of Americans who are contingent workers.

In just a few years, Stocksy has grown to 900 photographer-members, carefully selected from more than 10,000 applications. It has 20 full-time employees at its headquarters in Victoria, British Columbia, and another five contractors who work remotely.

Hugh Sitton, a photographer based in Britain, is typical of the quality of talent Stocksy is attracting. His profile page on Stocksy showcases his globe-trotting style, from portraits of a Samburu tribesman in Kenya to Vietnamese women in a pond of lotus flowers. His images have sold to clients ranging from travel sites to financial institutions.

“The stock photography industry has become much more competitive, and many photographers are definitely struggling due to the current price war for images,” he said.

He said he found the Stocky site easy to upload photos, create a portfolio page and track his sales. And he likes the fact that any member of the cooperative can submit an idea for discussion or to be put to a vote.

When Ms. Wettlaufer and Mr. Livingstone set out to create Stocksy, they considered making it a nonprofit organization, but decided to form a digital cooperative (“Think more artist respect and support, less patchouli,” reads the website).

Stocksy is what’s known as a multi-stakeholder cooperative, with three classes of shares: one for executives, one for staff and a third class for photographers. There is no fee to join or annual dues; members pay just $1 for their share of stock. That collaborative approach has helped the upstart thrive in a crowded and competitive market.