w3 schools background image css code example

Example 1: css background image

background-image: url("image.png");
background-position: center;
background-repeat: no-repeat;
background-size: cover;

Example 2: how to add background image in css

.bg-img{
 background-image: url("../img/bookGlowing.jpg"); /*In case the picture is in another folder and you are in css folder*/
background-position: center;
background-repeat: no-repeat;
background-size: cover;
}