var num=1
img1 = new Image (170,150)
img1.src = "store1.jpg"
img2 = new Image ()
img2.src = "store2.jpg"
img3 = new Image ()
img3.src = "store3.jpg"
img4 = new Image ()
img4.src = "store4.jpg"

function slideshow()
{
num=num+1
if (num==5)
{num=1}
document.mypic.src=eval("img"+num+".src")
}
window.setInterval("slideshow()",4000);