Image consistency

Replace the old image at smaller viewports.

Before:
![screen shot 2014-07-03 at 10 59 01](https://cloud.githubusercontent.com/assets/1764158/3468049/1d127494-0299-11e4-8c5e-15f14d1f74ce.png)
After:
![screen shot 2014-07-03 at 10 59 30](https://cloud.githubusercontent.com/assets/1764158/3468050/22fdb21a-0299-11e4-875b-702f63e825f3.png)
CC @guardian/content-platforms