Selfies, cats and so many uploads: Our love affair with sharing photos

Snap + Share: Transmitting photographs from mail art to social networks, an exhibit on display through Aug. 4 at the San Francisco Museum of Modern Art, explores the way people have shared photographs over the history of the medium. Here's Dutch artist Erik Kessels' installation 24 Hrs in Photos, a mountain of 350,000 random photos uploaded to Flickr in a 24-hour period and piled in an 840-square-foot room.

Get up close to the photos and you spot moments frozen in time. Step back and they all run together.

A video projection titled Addressability displays Jeff Guess' custom software, which pulls the most recent selfie uploaded to Twitter in real time and deconstructs the image into its individual pixels using colorful floating shapes. Once an image is gone, a new one pops up in real time.

In the '70s, conceptual artist On Kawara sent mass-produced postcards to friends and colleagues imprinted with his waking time.

"By sending postcards in the 1970s with the messages, 'I got up at 8:15' or 'I got up at 8:22 a.m.,' he is asserting, 'I'm here, I exist, I'm a real person,'" said Clément Chéroux, senior curator of photography at SFMOMA. "And this is essentially what we are doing today with Snapchat and Instagram."

Equal parts digitized pixels and analog art, Snap + Share looks at how people have shared photos over time, first with postal systems and now the internet.

German artist Aram Bartholl transformed the red map icon used in Google Maps into a large-scale sculpture he typically installs in front of museums or city centers. A version now sits atop the San Francisco Museum of Modern Art downtown to mark the museum as both destination and center.

Here is Aram Bartholl's large-scale sculpture atop the San Francisco Museum of Modern Art, against the downtown-SF skyline.

Yes, that's a taxidermied cat peeking down from a hole in the ceiling at SFMOMA. There's probably no symbol of internet culture as pervasive as the cat. Visitors to the Snap + Share exhibit are, of course, encouraged to snap and share Eva and Franco Mattes' creation, titled Ceiling Cat.

In 1997, before phones had cameras, French software engineer Philippe Kahn, a proud new father, sent this grainy photo of his newborn daughter to family and friends. He did so using a contraption he cobbled together from his mobile phone, a digital camera and a linked online network.

This Casio camera took the photo of Philippe Kahn's newborn baby that was transmitted to family and friends via phone in 1997.

More than a thousand tiled videos from artist and programmer Kate Hollenbach's phone capture her habits, expression and neuroses as she texts, reads, uses GPS and answers emails.

Videos pulled from Kate Hollenbach's phone. The artist wanted to explore our dependence on phones and created an application that explores her own phone use over the course of a month.

Newspapers didn't always have Dropbox. Here's a United Press International wire photo transmitter from the '70s.