function RandImg()
{
    var imgobj = this.document.getElementById('random');
    newsrc = 'http://www.fysiotherapiedronten.nl/img/random' + get_random(3) + '.gif';

    imgobj.src = newsrc;
    imgobj.width = 177;
    imgobj.height = 302;
}

function get_random(base)
{
    var ranNum= Math.round(Math.random()*base);
    return ranNum;
}