How Someone Can Track You With a Photograph You Took

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Cell phone photos, like this one taken with actor James Franco, often contain GPS information Manuel Silvestri/Reuters

Chances are, if you're currently a living, breathing human, you take digital pictures.

No longer the provenance of fancy cameras, digital photographs can now be taken on pretty much every cell phone out there and uploaded to computers with equal ease and gusto. Today, 91 percent of American adults own cell phones, for a total of 285,649,000 potential citizens out there with cameras. And every one of those JPEGs you upload to your computer and to the web don't just contain images; they contain a slew of extra information, collectively called metadata, that could be used to track you down.

Metadata can be extremely useful to photographers; nearly all metadata includes information like the focal length used to take the photo and the photo's exposure. But more and more often, GPS-enabled cellphones and cameras mean metadata now includes where, as well as when, the photograph was taken—meaning if you post frequent JPEGs, RAWs or TIFFs to the Internet, people could well be tracking you by your photos.

This is not an idle threat. John McAfee, tech mogul and maker of the famous McAfee anti-virus software, was living in Belize in 2012 when he was sought by police as a “person of interest” in a murder case. Convinced the police had it in for him, he fled Belize for the jungles of Guatamala — only to be tracked down by a Twitter user when two reporters from Vice magazine, who’d joined him on his trek, posted photographs online with the metadata still included.

And there’s no need for Vice Magazine to be involved, either: anyone could be just as easily tracked by way of their Facebook photo album. Already websites have popped up aiming to raise awareness of the problem. The most well-known example, IKnowWhereYourCatLives.com, raises the privacy red flag by tracking public pictures of cats to their owner's homes. Despite the site-owner’s (truthful) claim that he’s only showing what’s already public, the site can be a creepfest to look at — especially if you’ve posted a picture of your cat taken, well, anywhere close to your home.

Luckily, if you'd prefer to post to Instagram without people knowing where or when you took your photos, stripping metadata is pretty easy. For mobile phones, CNET recommends simply disabling location settings for the cameras on iOS and Android; for photos that find themselves on a computer, there's plenty of freeware for Windows, Mac and Linux that will strip the metadata from files. Those more curious than paranoid can also read their photo's metadata in plaintext by right-clicking the photo and scrolling to “More Info” (on a Mac) or doing the same and then scrolling to “Properties” and then “Details” (on a Windows PC).   

And for those times when even stripping the metadata won't suffice? Well, there's always old-fashioned film.