<img src="http://photosku.com/images_file/small_images/s005_537.jpg" />
<img src="http://photosku.com/images_file/small_images/s005_537.jpg" />
img:last-child{
opacity:0.4;
filter:alpha(opacity=40); /*  IE8 及更早的版本 */	
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.