var artImages = new Array();

pushArtImage("http://industrynano.ru/images/thumb/1.jpeg");


function pushArtImage(src){
var i = artImages.length;
artImages[i] = src;
}

if(!artImages.length){
document.write('<img src="/imgs/art.jpg" border=0 width=684 height=270>');
} else {
// get random number
var len = artImages.length;
var num = Math.floor(Math.random()*len);
document.write('<img src="'+artImages[num]+'" border=0 width=684 height=270>');
}