I use a suddenly popular internet app to see how old certain Diamondbacks REALLY are. Results vary.
On the internet zietgiest yesterda, the website http://how-old.net/ came into view. The premise is simple, you upload a picture of someone, and it guesses at their age and gender. From what I found, it's pretty good at the second part, and varies on the first. I uploaded a picture of myself and it said 28, which is weird because that is my actual age. However, other pictures I've uploaded show me in my late 30s which is rude.
But you can use this for pictures other than you and your immediate friends.