Add image behind header (Hayden template)

Hi

First time posting 🙂

Looking to find out if I can add an image behind my top level navigation rather than just having a colour. This is the website https://begonia-pepper-2e75.squarespace.com/ password: hello

It's using the Hayden template.

Add to Home > Design > Custom CSS

header#header {
    background-image: url(https://beaverhero.com/wp-content/uploads/2019/06/trees-3464777_640-min.jpg);
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center;
}

1 hour ago, tuanphan said:

Add to Home > Design > Custom CSS

header#header {
    background-image: url(https://beaverhero.com/wp-content/uploads/2019/06/trees-3464777_640-min.jpg);
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center;
}

 

Thank you! That's perfect. Will work on a relevant image now.

But what size is the image for the site?   I am trying to replace the background and I want it to show but I don't know the size it needs to be in order for the  elements of it to show properly on the page behind either gallery block or products.    I hope someone can answer this.   I've seen posts dating back to 2018 asking this question with no answer.