Lou, Carl, and Jake, Wildwood, N.J.

After George Eastman introduced the handheld Kodak #1 camera in 1888, amateurs made millions of snapshots depicting friends and family, travels, and festive occasions such as weddings. Even while solidifying such thoroughly conventional behaviors, amateur photography developed a new pictorial language that privileged immediacy, spontaneity, and accident. Career photographers and art historians—but also antiques vendors and flea-market shoppers—have long recognized the value of the “snapshot aesthetic.” The rise of social media and smartphones in recent years has effectively ended the era of the snapshot as both a printed photograph and an image for a private audience.