Yes, this is a discussion, which means you're going to get all sorts of opinion
If you're going to speculate about a person's motives (insecurity), you should in fairness, expect others to speculate about yours.
That's not controversy, that's fair play.
I've earned my bachelor's and master's degree in cognitive-behavioral and developmental psychology, respectively. I've worked in addiction and law-enforcement and both in educational and professional settings, we're taught not to make arm-chair diagnoses of people's behavior.
People's motivations are extremely complicated, and you can't judge self-esteem, insecurity, jealousy or other complex emotions based on casual observation.
It is as likely that you are jealous as the the woman you're talking about is insecure.
I wouldn't place a money bet on either, because I'd need to know a lot about you both to speculate on either.
I would though ask, why do you care? So what if she is insecure? (It's possible), but she also could be well-adjusted. She also could be proud and confident - or maybe she just wasn't raised with nudity taboos.
I was raised in a family that has never considered nudity a big deal, especially partial nudity.
I do think a lot of people overshare on facebook, but that doesn't necessarily mean the people who share more information on facebook are any different mentally and emotionally from those of us who share less.
Every single post on facebook or here on 3FC or any form of communication online or in person can be construed as attention-seeking, but not all attention-seeking is based on insecurity (or if it is, its the type of insecurity we all share).