function displayRandomImage(imageName,array){
document.images[imageName].src=array[new Date().getTime()%array.length];
}
urls=["/files/art1.jpg","/files/art2.jpg","/files/art3.jpg","/files/art4.jpg","/files/art5.jpg", "/files/art6.jpg", "/files/art7.jpg", "/files/art8.jpg", "/files/art9.jpg", "/files/art10.jpg"]