Possible to add a full or column/body-width image to top of blog?

– Using a page for the blog
– used page builder to structure blog

Is it possible to add a full-width image, or ideally an image that spans the width of the body/content column (with a right sidebar), to the top of the blog, below or maybe IN the header? Kind of like what you show on these pages:

http://kriesi.at/themes/enfold/headers/

or kind of like what we have here now. I want that banner image of the whole company to show below our logo and nav menu, but above all the blog content:

http://blog.agilebits.com

I tried using the page builder’s image element, and that banner image is 1360px wide, but the image appears on the live page pretty scaled down, with no way to tell it to go full width.

Thanks!