[shuttertalk]

Just read this interesting article about steganography, or the technique of concealing encrypted or hidden messages without drawing attention to the medium itself. In this context, this programmer hides an entire audio file of a pop song in a innocuous looking image.

The basic idea is that you can take the lower, less significant bits of the color values, discard them, and then replace them with arbitrary data.... I took the most significant 5 bits of red, 6 of green, and 5 of blue, and kept them in tact. Then the lower bits of each of these RGB triplets would form 8 bits (The 3 remaining bits from red + 2 from green + 3 from blue), or one byte from the audio file. This meant a pretty easy and direct mapping so the math and decoding was straight forward.

http://qaa.ath.cx/PiggyPack.html

Next time you see an image on the internet ... you never know - it could have a hidden message!