The finger depicts what he thinks of the middle class, women, the ill and people of color. In Amerika, we are free to voice our opinions and this woman is doing so and she represents the above groups. It is also great to have a sense of humor. The finger is so common it is not vulgar anymore.
It's one thing to be defiant in your booking photo. That's okay, you're not amused, we get it. No one would be. But it is an entirely different thing altogether to be completely aggressive and displaying your anger to the officers, who, it should be noted, are just doing their jobs.
As much as I'm sure that Texas Governor Rick Perry would have liked to flipped the bird in his booking photo he is still the Governor and had the responsibility to respect all aspects of the legal process. Including fingerprinting and booking. Flipping the bird would have only served to make voters question his integrity even more than they do now.
I think that would have been a very immature thing to do. While I don't think he should have been arrested or even have charges against him, he is doing the mature thing by turning himself in and dealing with it like an adult. Only a child would use vulgarity to make his case.
This would have just further cemented his perception as an idiot completely unprepared to handle both his current position and the one that he seeks in 2016. It would have been fine with me if he did it because that would have been the end of his relevance, but for his purposes it would have been moronic.