spread the image across the page

Hi. I’m a noob here so bear with me. I’m using Swift theme and I’m trying to make a banner using this model: sauditransformers.com. I figured that the red plane behind the swf is an image spread across the page.

How should I change my settings because the my banner has limited width? I tried to change it to 100% but it’s still bounded. I’m thinking if there’s a way to put an image behind the swf file but any image is also bounded. Thanks in advance.