Firefox compatibility and simplify gallery images layout 

#152, #203 

![screen shot 2014-02-10 at 11 41 50 am](https://f.cloud.github.com/assets/2622152/2124047/9f530d6a-9237-11e3-8504-2ce6ca377193.png)
![screen shot 2014-02-10 at 11 41 37 am](https://f.cloud.github.com/assets/2622152/2124048/9f55d7b6-9237-11e3-85f2-3b62e5dca4bd.png)

![screen shot 2014-02-10 at 10 22 45 am](https://f.cloud.github.com/assets/2622152/2124035/7b51f3d6-9237-11e3-85cf-ec2da3bdaeab.png)
![screen shot 2014-02-10 at 10 23 22 am](https://f.cloud.github.com/assets/2622152/2124036/7b591fd0-9237-11e3-8824-62d872c53a0e.png)