Virtue help

I have been using the Virtue theme for a couple of my sites and have been impressed by the theme. I have a question that I can’t seem to figure out about the Site Wide Banner. I like that the image scales down when using tablet or mobile devices, whereas the header background image was only zooming on a portion of the image, but I would really like to be able to have the Banner display different images on different pages. Not every page will be different, but I would like to have some change when going from certain pages to another. I have tried doing this with CSS by targeting a background image, but to no avail. Any help that anyone can supply, I would really appreciate it.