When Ashley Buchanan, a graduate student from Tampa, Fla., visited New York City a few weeks ago, she skipped the Statue of Liberty, the Empire State Building and the top of Rockefeller Center and headed to a tourist attraction she had bookmarked after seeing someone posing beside it on Instagram: the pink door of a restaurant on Delancey Street.

“You know what the big cities are, so it’s: What else can you see in a city? What’s new? What’s exciting? What’s beautiful?” said Ms. Buchanan, who swiftly uploaded a picture on Instagram of her posing before the doors of the restaurant, Sel Rrose, on the Lower East Side. “I don’t know why more restaurants aren’t doing this,” she said. “You could become super successful by just painting a wall pink.”

The photo-sharing site Instagram is a birthplace of its own culture, with influencers (humans, dogs and even monkeys) who promote brands or are professionally fabulous. But within the app’s endless photo stream, amid the silent competition for the best cappuccino foam or the perfect backdrop, a new style of travel has emerged: people who build their itineraries around the images, and seek out not, say, places like the Metropolitan Museum of Art for what it is, but also for the cool wall where they can pose in front of and post on social media.