how to create a css to use different image resolutions

I am trying to create a css file which will accommodate for two different images (same image but different resolutions). How do i accomplish this? Here is a sample code of how am getting the 1024 image done. Any pointers will be appreciated.
Thanks

#home{
	list-style-image: url("chrome://project/content/images/toolbar/1024 wide/banner_new_normal.png");	
	-moz-image-region: rect(0px, 445px, 79px, 326px);
}