Why do people upload photos to Facebook? What do they hope to achieve?

Why do people upload photos to Facebook? It's mostly women who do the uploading in my experience considering whenever I log onto Facebook I see 50 new albums on my wall and most of those are from my female friends. But why would you upload your vacation photos, photos of yourself at the beach, photos of yourself drinking and partying, photos of yourself inside your house. It so dangerous yet people are stupid enough to do it. Why? Do they want to feel validated? Are they bragging to their friends? Are they putting up a false front, kind of a "look at me I have the perfect life" deal? It just doesn't make since, who even looks at other peoples photos and why would you? What do you stand to gain from looking at your friends drunken frat party photos? I would really like to know why you upload photos to Facebook. I believe it's showing off to your friends and relatives.