how to add a background css code example

Example 1: add background image in css

.w {
background-image: url("images/tom1.png");
}

.a {
background-image: url("images/tom2.png");
}

.s {
background-image: url("images/tom3.png");
}

Example 2: background css

body {
  background: #ffffff url("img_tree.png") no-repeat fixed right top;
}