function changeBigImg(id, file){

	document.images[id].src = file;
}

function exchangeImg(id, imgary, cnt){

	var str = document.images[id].src;
	var idx = str.lastIndexOf('/');
	idx = str.lastIndexOf('/', idx - 1);
	var str2 = str.substr(idx + 1);

	var y = 0;
	for (x=0; x < cnt; x++){
		if(str2 == imgary[x]){
			y = x;
		}
	}

	y++;
	if (y == cnt){
		y = 0;
	}

	setTimeout('changeBigImg(\''+id+'\', \''+imgary[y]+'\')', 6000);

}