As a slightly overweight person this troubles me

I

When you look in a mirror, you see a better version of yourself (how your brain think you should look) but pictures are entirely a different concept :( I feel you

Nah its cos in the mirror you're moving and you look normal but in a photo your body is frozen and that seems unatural so you look worse.

Think about a beautiful sunset full of wonderful colors. You want to capture the image because it looks so beautiful. You get a camera and snap a few shots. Later on you look at the pictures, and each and every one of them look like crap. Just because your camera thinks you don't look good doesn't mean you do.