Style tweaks and fixes for image close button

Fixes #9

Adjust the sizing and padding of the image close buttons

Also moves it over to the right side, like how it appears in Linkinius

![screen shot 2014-10-24 at 11 49 04 am](https://cloud.githubusercontent.com/assets/168193/4774671/7e41e3b6-5baf-11e4-9c4d-5ed68c7aa86f.png)