var img=new Array()

img[0]="http://www.rocinantes.org/eng/img/topimage.jpg"
img[1]="http://www.rocinantes.org/eng/img/topimage01.jpg"
img[2]="http://www.rocinantes.org/eng/img/topimage02.jpg"
img[3]="http://www.rocinantes.org/eng/img/topimage03.jpg"
img[4]="http://www.rocinantes.org/eng/img/topimage04.jpg"
img[5]="http://www.rocinantes.org/eng/img/topimage05.jpg"

var r=Math.floor(Math.random()*img.length)
document.write('<img src="'+img[r]+'" width=730 height=220>');