Depends on how much the girl is into you.
If she is really into you she'll send it first if you ask (even if she already asked you first). You'll just have to wear her down.
If she isn't that into you, your pic might be the deal breaker. If you are attractive send it. If not, I would follow what Style did. Send it with some type of social proof. For example, he would send a pic of him from a magazine article about him. Tons of social proof there.
I doubt you have a magazine article written about you, but I'm sure you can come up with something clever to show value.