"The lack of words, the immediacy, it changed everything up," Bamberger said. "Artists like that. They're not big fans of tedious explanations or big, long discussions. They like fewer words, more pictures."
As an image-sharing social network, it also far surpasses the competition. Flickr, the photo-sharing service that Yahoo bought in 2005, has around 90 million monthly active users. Pinterest, a visual bookmarking website, recently crossed 200 million monthly active users. Instagram is on track to reach a billion monthly active users this year.
The coalescence of tech, demographics and changing buying habits also plays a role in making Instagram the tool of choice for art professionals. In the Venn diagram of people who use Instagram and people who are discovering and willing to buy art online, the overlap is increasing. Around a third of online adults in the U.S. use Instagram, according to research from Pew. Among those ages 18-29, usage shoots up to 59 percent. In its 2017 survey, art marketplace Invaluable found that nearly 56 percent of U.S. consumers ages 18-24 said they would buy art online, and 45 percent said social media is the main way they discover art.
"That's a very young group," said Andrew Gully, a spokesman for Invaluable. Given that most people don't start collecting art until later in life when they have the resources for it, Gully said if young people are already looking at and buying art online, the trend will only grow. "As they age into a collecting demographic, think of the buying power that group will have," he said.
While art sales from big auction houses such as Sotheby's and Christie's are well-documented, there isn't a lot of data on private art sales, and it's hard to say whether direct sales over Instagram are cannibalizing gallery sales. Anecdotally, though, auction houses and galleries are seeing their own sales increase as their work gets discovered on Instagram.
Major galleries, such as Saatchi in London, and museums including the Whitney in New York City and the Los Angeles County Museum of Art have cultivated enormous followings on Instagram. The museums use the service to promote upcoming shows, give followers a behind-the-scenes look at their operations and make art itself more accessible.
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"Social media is a space where we get to be especially playful. Everyone loves sharing a good Caturday image, so why can't we?" said Eva Recinos, social media manager at LACMA, which has more than 650,000 Instagram followers (Caturday is a portmanteau of "cat" and "Saturday" that appears frequently on the service). "That post could pique someone's curiosity about Japanese art or get them to explore our collections page for more artworks."
It has worked the other way, too, with museum visitors helping build awareness of LACMA by posting photos from the museum to their own Instagram pages. "Urban Light," the large-scale sculpture of lampposts outside LACMA's entrance, has become "an icon of Los Angeles, and that's due in large part to Instagram," Recinos said.
At smaller galleries, such as San Francisco's Guerrero Gallery, owner Andres Guerrero primarily uses Instagram to find new artists. The gallery's staff most recently discovered Sacramento artist Maija Peeples-Bright after seeing her work on Instagram, which resulted in a showing in the gallery's main exhibition earlier this year.
Curators such as Rosa Tyhurst, who previously relied on gallery and museum mailing lists and art shows to discover new artists, have also added Instagram to their toolbox.