Thanks...I didn't know I could add that without messing things up. I will experiment to see if I can use percentages in there. It would be great to use:
{include file="common/image.tpl" obj_id=$page.page_id images=$page.main_pair image_width=100%}
I'm hoping the result would be the image would fill the space (assuming it was big enough to fill it) but then maintain its aspect ratio. Thanks for your help and I will add my test results here for future reference.