Edit in JSFiddle

window.onload = function () {
    
    var paper = Raphael(0, 0, "100%", "100%");
    paper.image("http://dl.dropbox.com/u/63305355/bouningen.gif",
                10,10,80,80);
    
};

<div id="canvas"></div>

body,html
{
    height:100%;
    margin:0;
}

#canvas 
{
    height:99%;
    background:#fff;
    text-align:center;
    padding-top:180px
}