Take screen_shot if the page don't have images

## before 
![](http://gyazo.l0o0l.co/img/2014-05-16/5d94e8e1866f2ed5e1c97b1d1a12dd61.png)

## after 
![](http://gyazo.l0o0l.co/img/2014-05-16/f304e7ebbf237a5da34c9bdbfc95410f.png)