Making images full-width

Site URL: https://kellychangz.com/

How do I make images and galleries full width? I'd love to know how to identify these blocks and add CSS to make them full width

Thanks!

First screenshot: https://kellychangz.com/pandora-community

Second screenshot: https://kellychangz.com/new-page-3

PASSWORD: stars

With gallery, add to Page Settings > Advanced > Header

<style>
  main#page {
    width: 100%;
    max-width: 100%;
    padding-left: 0;
    padding-right: 0;
}
</style>

With images

I see many images on above link, you just want fullwidth first image or all?