aImgs = new Array();
aImgs[0] = 'images/1-fussballer.jpg';
aImgs[1] = 'images/1-mann_frau.jpg';
aImgs[2] = 'images/1-frau.jpg';
aImgs[3] = 'images/1-frosch.jpg';
iIndex = Math.round(Math.random() * aImgs.length);

function zufall()
{
/// alert(iIndex)
if(iIndex >= aImgs.length)
{
document.bild.src = aImgs[2]
return false
}
document.bild.src = aImgs[iIndex]
}