body{
    background-image: url("/Start Page/background.gif");
    background-size : 80%;
    background-position : center;
    }
      
html, body{
    height: 100%;
    margin:0;
    padding:0;
    }

div{
    position:relative;
    height: 100%;
    width:100%;
    }

div img{
    position:absolute;
    top:0;
    left:0;
    right:0;
    bottom:0;
    margin:auto;
    }