img {
content: url("/path/here/to/image.png");
}
#divID {
background-image: url("http://imageurlhere.com");
background-repeat: no-repeat;
width: auto; /*or your image's width*/
height: auto; /*or your image's height*/
margin: 0;
padding: 0;
}
img {
height: auto;
width: 500px;
}