var img = new Array();
var img_anzahl = 6;
// preload images
for (i=1; i<=img_anzahl; i++) {	
		img[i] = new Image();
		img[i].src = "images/visual_" + i + ".jpg";

}


function randInt(min,max)
{
        var div = (max - min) + 1
        var randNum = Math.random()
        for (var i = 0; i <= div - 1; i++)
        {
                if (randNum >= i / div && randNum < (i+1) / div)
                        {return i + min}
        }
}

function writeVisual(){

	document.write('<img src="images/visual_'+ randInt(1,img_anzahl)+'.jpg" width="260" height="79" border="0" alt=""><br>');
}