Good question, it's kind of hard putting to words, but you know how sometimes you meet a guy and you just feel that he is gay? You can't really explain it , it just combination of style and how he caries himself even if he is playing to be straight, you can call "bullshit" in your head. Girls feels the same way to an extend when they see pics of guys who look feminine. Take a look at my Instagram for examples of "masculine" photos.I got plenty of examples there. Also, you can just google image "masculine" vs. "feminine" guys.