Adding a background image that goes from top navigation down to the footer

Hi,

If you share a page url, we can help easier

You can also try adding this code to Page Header Code Injection

<style>
  .section-background, .page-section, .section-border {
    background: transparent !important;
}
body {
   background-image: url(https://cdn.pixabay.com/photo/2021/01/07/22/15/dandelion-5898546__340.jpg);
   background-size: cover;
   background-repeat: no-repeat;
   background-position: center center;
   background-color: transparent !important;
}
</style>