Image across sidebar and main

Hi,

I am trying to put an image below header that would stretch across sidebar and main page. This image would be the same for all the pages in one section. The best I could come up with is using a slider, but it would be irritating for the user to start the slider over and over again when he goes from one page to another.

How do I put a simple image in this position? Alternatively, is there any way for the slider to show the fixed image without any transitions?

The site is http://test.kagor.hr/zasto-pisati-poslovni-plan-ili-investicijsku-studiju/

Many thanks.