The iPhone may be one of the most popular cameras in the world today, but it hasn't always been like that. The original iPhone (and the iPhone 3G) had just a 2MP camera, with no flash, putting the handset well behind the competition in terms of photo-taking.
Since the 3G, however, Apple has made sure to update the phone's camera with ever iteration. It went from a 3.2MP sensor to a 5, and then to 8. And wouldn't you know it, someone has created an image showing its improvement in picture quality over the years...