how to put button on background image css code example

Example: how to set background image for button in css

div#submitForm input {
  background: url("../images/buttonbg.png") no-repeat scroll 0 0 transparent;
  color: #000000;
  cursor: pointer;
  font-weight: bold;
  height: 20px;
  padding-bottom: 2px;
  width: 75px;
}