What's the difference between these two girls?

People probably assume that Girl 2 has slept with several guys because of her partying ways so they give her less respect because they think she's "easy." Also, if she shows off her body with the clothes she wears, people can also take that as a sign of being "loose." Where as Girl 1 doesn't seem like that so they don't think of her as someone who sleeps around. So yeah, it's basically just assumptions and judgments about both girls.