I am having a problem with my subcategory header image display. I don't know if I can fix this in the admin control panel, css, or which page I need to modify to add css to control this layout.

We want our category header images to look like this: http://www.lasilhouettelingerie.com/...ves-c-193_197/
The problem is our category pages that contain subcategories look like this: http://www.lasilhouettelingerie.com/...ssories-c-193/

We want the header large 750px X 150px on the pages that have products, but not on the subcategory page. In the second example above, we do not want these subcategory images to show. If we do decide we want images here in the future, we will want them a different size (not 750px X 150px). How can I distinguish between the two?

I know about: configuration>images and I have been playing around but do not see these banners disappear on my subcategory pages.