I can offer a way to create a header across the full width of the native blog post page. It’s not perfect, but pretty good. Create a post which starts off with an image. Using PageBuilder set up a single column row, and insert the SiteOrigin image widget, and upload an image. Click on the “Edit Row” option in the menu that that appears when you hover over the spanner of that row in Pagebuilder. In the window that comes up, go to the “Row Styles” menu on the right, click on “Layout”, scroll down to “Row Layout” and in the box select “Full Width Stretched”. Click “Done” at the bottom right hand corner of the window. You will be returned to the main editing page of the post. In the “Publish” box at the top of the right hand column, edit the “visibility” to make the post sticky. You will now have a post that has an image full-width across the whole blog page. Of course you can add to the post, below this image, any text you like through inserting further rows using PageBuilder. Do not give the post a name. This image now appears at the top of the native blog page, full width across the page.
The flaw is that on the blog page, showing through the left hand side of the image is a date of posting, which is also a link to the original post which is the source of the header now appearing across the blog page. Maybe someone in the forum may know how to get rid of this date?
Thanks, Joe B