When ever you take a picture with a digital camera, there is data embedded into the file you just took, called EXIF data. This holds the data of the time of the shot, ie: Camera model, shutter speed, aperture, focal length, etc etc. You can look for yourself. Just navigate to a picture you shot, right click and do properties. Hit the summary tab and click the Advanced button.
The lesson to be learned here is that the EXIF also saves the thumbnail of the original picture. So say you took a pic of you and your dog, you crop the dog out of it and post the pic on your blog. I can then save that pic, extract the EXIF data and see the thumbnail or the original file with the dog. Eh, doesn't sound important right?
Well some tech-geek hot chick from G4tv, Cat Shwartz, posted pics of herself on her blog:
Obviously she cropped out her boobs. But apparently some desperate kid saved these pics and as he went to retrieve them, he saw the topless pictures of her in the thumbnails.
No nudey pics here but they can be seen here, make sure you turn off the google filter: http://images.google.com/images?hl=en&q=cat%20schwartz&um=1&ie=UTF-8&sa=N&tab=wi. It's not that great, but hey, they're boobies.