Unable to insert image above content below menu

Hi everyone

I have been trying for ages and have been unable to insert a banner image on top of content on my webpage below the menu; I would also like to do this, perhaps at a future time with different banner images in different pages. I dont know any HTML or CSS so if anyone can explain or help me do this in a simple way I would greatly appreciate it.

I also want this to have cross browser compatibility. I say this because I tried unsuccessfully to do this by inseting the image in hte background and it ended up being a mess…

My website is http://www.etsiarts.com and what I want to achieve is something like this http://www.wowakk.com/.

Once again I would really appreciate any help as I cant find any guidance despite my best efforts on how to do this.

Andreas