Sidebar start after full sized image

This is for the main page at NRMG.org

Hi there,

I believe the header element is what you are looking for:
https://docs.generatepress.com/article/header-element-overview/
https://docs.generatepress.com/article/page-hero-examples/

Let me know if this helps :)

Wow this is exactly what I was looking for!! Thanks so much!!

You can see this implemented at NRMG.org now. Would it be possible to make the background fixed so that it doesn't move as the user scrolls up or down the page?

I would recommend trying the built-in parallax effect:
https://docs.generatepress.com/article/header-element-overview/#page-hero

Or you can try this CSS:

.page-hero {
    background-attachment: fixed;
}

Awesome that's exactly the code I needed :-)

No problem :)