var ry = 1;

function random_topimage_left(pre){

ry=Math.floor(Math.random()*4)
if (ry==0)
ry=1
if (ry==4)
ry=3
document.write('<img src="'+pre+'top_images/ubach1_'+ry+'.jpg" width="71" height="65">')
}

function random_topimage_right(pre){

document.write('<img src="'+pre+'top_images/ubach2_'+ry+'.jpg" width="246" height="65">')
}