Answer of yesterday's game

Although it is not 24 hours yet, I still want to give the answer and solution to you.
As some of you may know, what I did is to hide the most significant 4-bits/ 3-bits of an image to the least significant bits of each pixel of the photo. It is the reason why the photo did not change much after this modification. The reverse is also very intuitive, I will leave it to you.

Here is the image hidden in each photo.

Encode	Decode

photos taken by Sam Rohn - Location Scout

Here is my source code, which is written in python. If you want to run this code, you need to have the package Python Imaging Library (PIL).

Reference:
http://en.wikipedia.org/wiki/Steganography
http://www.pythonware.com/products/pil/
http://petitcolas.net/fabien/steganography/
http://utilitymill.com/utility/Steganography_Encode