Pictures of cats, as cute or as grumpy as they can be, can offer clues to the location of their owners.

Pictures of cats, as cute or as grumpy as they can be, can offer clues to the location of their owners.

Your cat may never give up your secrets. But your cat photos might.

Using cat pictures — that essential building block of the Internet — and a supercomputer, a Florida State University professor has built a site that shows the locations of the cats (at least at some point in time, given their nature) and, presumably, of their owners.

Owen Mundy, an assistant professor of art who studies the relationship between data and the public, created “I Know Where Your Cat Lives” as a way of demonstrating “the status quo of personal data usage by startups and international megacorps who are riding the wave of decreased privacy for all,” Mr. Mundy wrote in a post about the site.

Using images of cats uploaded to photosharing services, including Flickr, Twitpic and Instagram, Mr. Mundy extracted latitude and longitude coordinates that many modern cameras, especially those in smartphones, attach to each image. His site displays random images from a sample of one million of the many millions of pictures tagged with the word “cat” online.

The images are displayed on a map using satellite imagery, with nearby cat photos also visible. Specific street addresses are not displayed, but the geographic information can leave few details to the imagination in rural areas.

Not all of the images are of cats; some are of a picture of a picture of a cat, acat owner or even a brochure for a production of “Alice in Wonderland” with the Cheshire cat’s smile. They come from around the world, although images from the United States, Russia, Britain and Brazil top the list of locations.

The owners of cats captured by the site might ask: What can I do to remove my cat’s picture from it? Although such an action seemingly goes against the very nature of the Internet itself, the answer is pretty simple, according to the site: “The way you would go about doing so is by increasing the privacy settings of the photos of your furry feline friends. Then within 30 days your photos will be gone from our site.”

The lesson for people who share pictures online, whether it’s kittens or your children, is this: If you include more metadata than you have to with your photos — there are tools to scrub that data — don’t be surprised if it’s used online in ways you didn’t expect and can’t fully control.

New York Times