I think that in general, as Laura notes and T99 supports, Hillary's appearance is commented on far more than any male candidate. For women of a certain percentage of feminism (of whatever wave) in their bones, it is a default position to be annoyed at that. I think that is a reasonable general rule. I don't think it applies in Hillary Clinton's case. Men have a very narrow range, and it is considered a major screw-up if they deviate from that in any public photograph, such as Bush in crocs, or Obama in something too informal. So it's simple for them, really. Safe.
But there are safe choices for women as well. Most female politicians use them. Sarah Palin had some nasty comments directed at her for her hair and glasses, but she was electing to appeal to Her People. The women who hated that look for cultural reasons skewered her. And notice, she wasn't that different. She could have dressed like Nikki Haley instead - within the range but pushing the edges. Sometimes she did, sometimes not. She got kicked just about as much as she deviated. Same as the men. No one is forcing Hillary Clinton to wear yellow Mao jackets. The comments don't come up for men because the short guys, the bald guys, the fat guys, the guys with glasses, the guys who wear elbow patches or Hawaiian shirts or feed caps/ball caps are pretty much dead in the water right out of the gate.
Elizabeth Warren, Barbara Boxer, Diane Feinstein, Nancy Pelosi, Patty Murray, Mary Landrieu, Kirsten Gillibrand, Kelly Ayotte, Michele Bachman, Condoleeza Rice...they dress the same. They don't get a lot of flak. Hillary doesn't dress that way. There's a reason for that, and she owns it. She wants to be something else, a celebrity, an icon, a superstar.
She has an expressive face, which is probably a charming thing in person, but leads to many unflattering photos. The Wymans are very familiar with this, and you will notice that we don't run for public office for related reasons. That's not fair? The general public should admire her for her policy positions? Or her character? Gosh darn it, the sexism never ends, does it? What would Antonin Scalia say? Or Ruth Bader Ginsburg?