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Ever heard of EXIF ? Neither had I until recent. EXIF (Exchangeable Image File) is data stored in JPEG and TIFF image files, such as shutter speed, date and time, focal length, exposure compensation, metering pattern, image source, date for edit and if a flash was used a the time a photo was taken.

But EXIF also stores more information than that.

If you’re a fan of the CSI series (or any other crime fighting series), you have undoubtedly seen that they from time to time try to verify if a photo has been altered in any way. What they draw their conclusion on, is the EXIF Data stored in the file. What they don’t tell you is that some equipment also stores your GPS-position which may lead someone to your home adress, phonenumber, income etc.

Personal information at stray

In todays digital world, many share their photos on sites like Facebook, Twitter etc. without any concern. Some may blur out faces and other revealing “information” in the photos, but leave personal information available for anyone who knows where to look.

First off, NOT ALL photo equipment store personal information. But how do you know that yours don’t – if you don’t check ?

There are some Cameras that has GPS or GeoTagging features. But for the most part, Cellphones are the ultimate culprit as many nowadays have built-in GPS.

Imagine this scenario: You take pictures around your house, showing off the expensive home cinema system, new car, cellphone etc. You upload these pictures to your public folder. If any of these pictures have your GPS-Location stored in the EXIF, anyone can find your address from the GPS Coordinates (using Google Maps). Then a quick search on Yellow Pages (or similar) reveals who lives at the address, then a new search can reveal your phone number, your tax and income and so on. All of which can lead to identity theft.

Try for your self, and see if you can figure out who lives here.

I’m not writing this to scare you, but… well, okay maybe I am… Just a little…

Cameras

Cameras such as the Ricoh Caplio 500SE, Nikon Coolpix P6000 or some higher-end mobile phones, have a built-in GPS receiver and store the location-information in the EXIF header. Recorded GPS data can also be added to any digital photograph on a computer, either by correlating the time stamps of the photographs with a GPS record from a hand-held GPS receiver or manually using a map or mapping software. The process of adding geographic information to a photograph is known as geocoding. Photo sharing communities like Panoramio, locr or Flickr equally allow their users to upload geocoded pictures or to add geolocation information online.

Cellphones

Most of Nokia’s N-series mobile phones (such as the N95) are equipped with a GPS receiver, using Location Tagger all  images are tagged with corresponding GPS coordinates when GPS signal is available.

The second generation of iPhone (known as the iPhone 3G) by Apple Inc. is also equipped with a GPS receiver, and uses the receiver to GeoTag photographs taken with the device. I’m sure this also applies to Generation 4.

The first generation iPhone is not equipped with GPS, but use a service provided by Skyhook to triangulate and approximate the location (at which the picture was taken) using nearby cellular phone towers and WiFi hot-spot signal strength data. The Skyhook service provides approximate location information which is then added to the EXIF-data associated with the picture.

Also mobile phones with the Android operating system can GeoTag images with the included camera application.

How to check your images

The EXIF information can be read by a number of programs, called EXIF Readers. Not every program can read all the information, depending on how new your equipment is or which EXIF version it supports. I use a free program called KUSO Exif Viewer.

KUSO Exif Viewer can search online maps like yahoo maps, googlemaps etc. using the GPS information found in your image.

Download KUSO [Freeware]

Ensure your privacy

Before you upload a photo to an online site, make sure you first remove any (or all) EXIF information stored in your photo. This can be done with free programs like EXIF Tag Remover. These programs remove what is considered private data. A side from protecting your privacy, you also get smaller image sizes as a bonus.

Download EXIF Delete [Freeware]

Edit or Modify Exif Information

Another program that not only allow you to view or delete EXIF information is a Shareware tool called: Opanda PowerExif Editor. Which also allow you to edit and add Exif Data. My reason for mentioning this last, is that this actually not a free program thou they distribute a light version as shareware.

Download Opanda [Shareware]

To summarize

If you want to protect your privacy, Make sure you really delete all personal information from your images, not just the visible parts.

Sources:

http://en.wikipedia.org/wiki/Exif

http://www.digicamhelp.com/glossary/digital-photography-glossary/

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