Header Image – How to Suppress on Posts

Header image (black & white photo of meeting table) appears on all static pages, which is fine. But when I go to create a post, it continues to appear at the top of each page. I would prefer a blank post page with only the site ID (upper left) and the page menu along the top. I would like to suppress the header image on posts and only add images that are relevant to the post, as desired. Any help appreciated.

The page I need help with: [log in to see the link]