Using a good image is the best way to describe something as complex as a consumer segment. Putting a page loaded with bullets: young, Asian, affluent, female, confident, well-educated on a piece of paper does not get the message across. A picture does the trick: hey, here she is!
Finding good, non-cheesy, non-artifical-model images is a challenge though.
Visualization of a person is helpful in another way: preparing your presentation. Putting up that picture of a "typical" CIO of a medium-sized company might put you in the right "mood" to fine tune that important sales presentation for 200 blade servers. The picture itself of course will never make it into the final presentation (it might if the audience has a sense of humer, but it is extremely high risk).
Our Asian consumer image was purchased on iStockPhoto.