If so, how do I get the image to show above the header? Do I hide the header?
Anything is possible if you think outside the box... Perhaps if you explain more of what you are trying to achieve, we can help you out better. On this image, I am not really seeing a header (Per Se). If thats the case, build the section how you want, and hide the header on just that page.
Go into the Header, Edit Design, toogle ON 'Overlap first row on this page' do this on Mobile as well. This will get you most of the way there.
Maybe this will help. How can I have the image on the landing page under Row 1, Column 1 overlay over the header when editing the site?
In that case @Robert_Tickner provided the right answer.