Fix lightbox image covered by status bar

Before:
![image](https://cloud.githubusercontent.com/assets/1073082/5431829/da8e1876-846b-11e4-903a-28aee9afee06.png)

After:
![image](https://cloud.githubusercontent.com/assets/1073082/5431827/cdaa8608-846b-11e4-8646-426c4625a5c3.png)