how to add background image in css

1background-image: url("image.png");
2background-position: center;
3background-repeat: no-repeat;
4background-size: cover;

1<style>
2body {
3  background-image: url('img_girl.jpg');
4  background-repeat: no-repeat;
5  background-attachment: fixed;
6  background-size: cover;
7}
8</style>

1body {
2 background-image: url("paper.gif");
3 background-color: #cccccc;
4}

1.wrapper {
2    background: url('./images/homeBg.png') no-repeat;
3    background-size: 100vw; 
4    float: left;
5    height: 100vw;
6    width: 100vw;
7} 

1.selector {
2  background-image: url(image.png);
3}

1.bg-img{
2 background-image: url("../img/bookGlowing.jpg"); /*In case the picture is in another folder and you are in css folder*/
3background-position: center;
4background-repeat: no-repeat;
5background-size: cover;
6}