Hi all

I am new at the forum and this is my first post. And I get here already needing help from you.
I am trying to customize a friend's store, but I must confess that I am not been able to set the store layout as requested by my friend.
she wants a layout that be in the style of the url bellow.
http://www.digitalfreebies.com/store/
Note that in this URl there is an image that fits itself in the header image, and thus completing the design.
I tried to put this image as background image in the body, but it came out not aligned with the mainWrapper and with header_bg.
Please, could anyone help me coaching me on what to do so this image becomes aligned to the store header and body?
In which place on the template or in css should I include this image?
If I include it as bg in the mainWrapper, the body of the store goes along and it becomes non-aligned.
Did I make myself clear about the help that I need?
Please, can anyone helpme?
I am using zen cart latest version.
Thank you in advance for all and any help that I could get .
Tito