Having a good picture of yourself can do wonders for your self esteem. I don’t just say that simply because I’m a photographer - It’s important to know what you really look like, in proper lighting.
Sadly, one of the most common things I’ve heard over the course of my career is: “I don’t like looking at myself in pictures.”
I’d argue that people are NOT use to seeing themselves as they are seen by others, but only through mirrors, which is a reversed image - a reflection. The difference between your reflection and photo are subtle, but it can make you feel like you're looking at two different people, which can trigger insecurity.
It’s important to see yourself in the best light, often, so you grow comfortable with your image - period.