Good job on visualization! The graphs that show selfies on hover are great. How did you measure level of smile? Do you have an algorithm or you went through the photos manually?
"In the resulting set of selfie images, we ran automatic face analysis, supplying us with algorithmic estimations of eye, nose and mouth positions, the degrees of different emotional expressions, etc."
"As the final step, one or two members of the project team examined all these photos manually. While most photos were tagged correctly, we found some mistakes."
See the section at http://selfiecity.net/#dataset .