#particles-js{position:absolute;top:0;left:0;width:100vw;height:100vh;z-index:1}.background-image{background-image:url(//wheel.bucci-composites.com/path/to/your/image.jpg);background-size:cover;background-position:center;width:100%;height:100vh;position:absolute;top:0;left:0;z-index:0}