This video from the MIT youtube channel describes how the picture is taken, and shows the result. A pulse of light being scattered through a plastic bottle.
From the MIT News article:
"After an hour, the researchers accumulate hundreds of thousands of data sets, each of which plots the one-dimensional positions of photons against their times of arrival. Raskar, Velten and other members of Raskar’s Camera Culture group at the Media Lab developed algorithms that can stitch that raw data into a set of sequential two-dimensional images."
The video and article go on to explain how this could be used in medical and chemical engineering processes. Where if you can determine how light scatters through a body, you can make ultrasounds with light pulses.
MIT News Office