UPDATE for Mac Users: looking for the same functionality on Mac OS X? Check this out.
Have you ever heard about steganography? Well, it's the equivalent to invisible ink in digital files. The idea is that you can hide data in digital images and still keep the normal appearance of the image.
For example, check out this picture:
Other than presenting a very strange cow, it appears to be a very normal picture. In fact, this picture hides a TXT file in it, where the location of the cow is revealed.
So, I got a challenge for you: using Hide in Picture (a steganography software that allows you to hide and retrieve files to and from pictures) try to retrieve the "location.txt" file from the picture. This way, you'll know where this picture was taken.
- use the original picture, not this small one (click this small picture to access the original picture european_cow.GIF)
- the password is the first word of this blog's URL
Source: Lifehacker's Geek to Live