Take a look at my Profile Image. Normally, someone with a little bit of knowledge could find out quite a bit of information about me just by checking the EXIF metadata of the image. Since I stole this particular image off the Internet, nothing much interesting can be revealed, besides the date and time I modified the image and the fact that I used Photoshop CS2 to modify it.
However, a photo taken by myself with my digital camera can tell you
- when the picture was taken,
- what camera make and model I used,
- what software I used to download the picture to my computer,
- when the picture was modified and
- what software I used to modify it.
If I’m using one of these GPS-enabled devices, you can even find out exactly WHERE I took the picture.
If you have one of those fancy new digital single-lens reflex cameras (e.g. Canon Digital Rebel) you’ve probably registered your camera with the manufacturer (Canon) for bonus crap, haven’t you? And since the “Camera Body No.” is stored in the EXIF information, the people at Canon (and NSA, if they want to) know what pictures YOU took (or someone using your camera).
Normally, EXIF is a Good ThingTM. The GPS camera, for example, was created to enable you to let your friends know where (and when) you took the picture. But as usual: beware of what you reveal to strangers. If tinfoil is your friend, you might want to remove that EXIF information before giving the picture to the entire world, without ever being able to remove it…
The simplest and best tool I’ve encountered for removing EXIF information is “Exif Farm“.
Unfortunately, EXIF Farm costs money (the demo sucks ass). However, there are numerous other tools available, including some Open Source ones.
ultraparanoid 
