"overflow: hidden" would also work on the container or parent div but I'm not sure what the size of the image is and it may produce undesirable results. If you used overflow: hidden, which would be typical in this case, you might have to mess with the div sizes of content-left and content-right
Quick note: using "overflow: none" is actually an invalid property and really isn't working as a container. You should probably add "overflow: hidden" and adjust the size of the content-right and content-left divs.
As an example if you added a div under "belowheaderwrap" it would appear behind it because "belowheaderwrap" has no height since it isn't containing anything.