Is there a good way to use CMS images with CSS

Question

I am building a responsive wordpress theme that allows for a custom banner image to be uploaded to each page. However, because of the responsive nature of the theme I need to set the images as background images using css to achieve the right effect. But, I do not want to throw random css styling into my html markup. Is there any to pull the image url from within the page template and drop it into a css file dynamically?

I found an example of what I am looking to do here but without the slider functionality.: http://emporiumpies.com/

It seems they are hard coding the images in the css file, but that is the visual effect I am going for. I just need to figure out how to tie this into the wordpress CMS.

Any help would be greatly appreciated! Thank you!