Based on this cover, I would have thought it was a very gender neutral looking person, and probably a lot less masculine if she wasn't frowning like that. But yeah, there's a huge difference between not being masculine enough vs. not being obviously a man.
I can imagine the second photo passing as male but not in a good way.
There are subtle body language differences between men and women and that may be a factor.
I'm tall for a woman. I've had very short hair for like fifteen years. It didn't initially get me mistaken for male.
After being homeless for a year, people began calling me "sir" if they initially saw me from the back. (I would turn around and they would apologize for their error.) That was partly due to clothing but probably also my body language changed in ways I was not conscious of.
There are myriad subtle details that help us distinguish male from female. It isn't any one thing.
Edit: I will add her hair is hair that is short for a woman but on the long side for a man. Men with long hair are often bearded. They have hair all over.
The photos are almost an uncanny valley in terms of trying to look like a man. Like she didn't quite get it but thought she did.