I'd like to make a file that takes an image captured from a webcam and generates two new images comprised of either half (left and right) of the original captured image.

I'll be capturing peoples faces and displaying back to the user either side of their face as a whole to assess how symmetrical a persons face is. Exactly how this website is doing it:

http://www.echoism.org/

If anyone could advise me on how to go about this project that would be much appreciated. Thank you.