So trying to figure out what infinitesimal percentage of the 657 billion photos uploaded to social-media sites this year I am in is, perhaps, a ridiculous idea. But that has not stopped me from trying.

First I tried to really narrow the question down as much as possible to this: How many photos that have been uploaded to social-media sites, and still exist on those sites, am I in the background of? This eliminates photos that may have never been uploaded, photos that may not exist online anymore, Snapchats, security cameras, and video footage of tourists who are recording their entire walk through a museum or monument.

The number of photographs you’re in is a direct function of the number of places you’ve been that are highly photographed. “If you go to many places around the world like the Taj Majal, it’s not as though every person in the world is visiting there, it’s some subset of people,” Schoenebeck says. In other words, rich people get to travel more, and are therefore probably in more photos.

To eliminate this variability, I decided to just try to estimate my own photo-footprint. So the first thing I did in my futile attempt to estimate this number, was make a list of all the places I’ve been that might be photography hot-spots. I live in New York City, so that’s one big place for photographs. And I’ve been to six of what TripAdvisor calls the “top 50 tourist attractions in the world.”

But how many photos are taken at each of those places? That’s hard to figure out too. Google has a site called Panaramio, a mashup of photo sharing and geo-tagging. And a site called Sitesmap shows how many photos have been uploaded to Panaramio in each location. But these are just photos that have been shared using Panaramio, which isn’t a particularly popular service. Looking at a single photo-sharing service like Flickr could give one sense, but it would be a small slice of the photographic pie. And on many social sites, geotags aren’t easily searchable.

Then there’s the question of whether any of this matters. Right now there are some number of photographs that include me in the background. So what?

“It’s like that thing about the tree falling in the forest,” Schoenebeck says “It’s so easy to take and delete digital photos, and you may not know they exist, you may never know they existed, what does that mean for your own digital identity? Does it even matter?”

Martin Hand, a sociologist at Queen’s University in Ontario, Canada, has the same question. “Unless you’ve got a tag, you’re not going to know you’re in it, unless you stumble across it. There are these ghost profiles floating around, sort of ephemeral versions of you that you’re unaware of. They’re kind of like wallpaper.”

Schoenebeck studies how parents and teens relate to digital photos—she looks at things like moms posting baby-photos online, and how teenagers feel about their earlier selves immortalized in digital images on Facebook. She and Hand both talked about how teens today take a lot of care in the photos they post. Instead of dumping all 30 photos they took at the Eiffel Tower into a Facebook album, they’ll post two. Their relationship with photos isn’t one of personal memory, but rather of public identity. Hand describes the thinking: “Of course you take images in order to distribute them, that’s what they’re for.”