I've seen pictures in the past where she looked unhealthy / fairly scrawny, but this is not one of them.
I'd say she's at the low end of her healthy weight, but she looks perfectly healthy and there's some muscle definition in the arms that would suggest she's not starving herself.
BTW, I have a BMI of 27 right now, so am slightly overweight and have no axe to grind as regards skinny-shaming.