var image_array = document.getElementsByTagName("img");
var i;
for(i=0;i<image_array.length;i++)
{
	if(image_array[i].width > 640)
	{
		image_array[i].style.width = '80%';
		image_array[i].style.height = '80%';
		image_array[i].style.cursor = 'pointer';
		image_array[i].title = '点击放大';
		image_array[i].onclick = function(){
		//location.href=this.src;
		window.open(this.src);
		}
	}
	
}