Oh God, this layout's code looks really wrong
Ok, for starters. You really shouldn't use <img> in a layout, as it will either stretch the page or look cut off to anyone who doesn't have the exact resolution to suit your background image. Layouts should be made entirely by <div> tags. That level image should be in the parent <div> with
bottom left repeat-x
Did you code this, or did someone else? I suggest a revision.
e: a big revision at that... it seems like the postbox's width is not even dynamic? what