How to add 3 images as back ground to an div

.img1 {

  width: 100px;

  height: 55px;

  margin: 0;

  padding: 0;

  border: 0;

  background: transparent url(./images/elevation.jpg) no-repeat center top;

  text-indent: -1000em;

  cursor: pointer; /* hand-shaped cursor */

  cursor: hand; /* for IE 5.x */

  width:100;

  height:100;

}

<asp:LinkButton ID="lnk" runat="server" CssClass="img1" Text="Click">

    </asp:LinkButton>