fixing blue image offset

The blue circle was offset to the right by 1 pixel.

Before:
![screen shot 2013-07-03 at 12 32 31 pm](https://f.cloud.github.com/assets/370976/744523/3e58598a-e3fe-11e2-81e2-c67485acdf7e.png)

After:
![screen shot 2013-07-03 at 12 32 41 pm](https://f.cloud.github.com/assets/370976/744524/3e5902d6-e3fe-11e2-9b97-468d3466b01f.png)