I Don't Understand Why Some People Post Pics of Themselves All the Time

I'm not saying this to be mean. But I just don't get it. Why?

Unless you're being funny, why?

There are some bloggers who post pics of themselves daily. IMO even weekly is excessive.

Why?

I'm guessing it's a little bit of everything.
I have my own theories/judgements but I'd really like to hear it from the people who do it.

Why?

I've always wanted to know.

Why?