Add theme preview image

Author: mmistakes

README.md

@@ -2,9 +2,14 @@
 
 Minimal Mistakes is a flexible two-column Jekyll theme. Perfect for hosting your personal site, blog, or portfolio on GitHub or self-hosting on your own server. As the name implies --- styling is purposely minimalistic to be enhanced and customized by you :smile:.
 
+[![Minimal Mistakes live preview][2]][1]
+
+[1]: https://mmistakes.github.io/minimal-mistakes/
+[2]: https://cloud.githubusercontent.com/assets/1376749/14562643/d83b96c0-02eb-11e6-98d6-473fbfd3bff6.jpg (live preview)
+
 The theme includes responsive layouts (`single`, `archive`, and `splash` pages) that look great on mobile and desktop browsers.
 
-![mm-layout-examples](https://cloud.githubusercontent.com/assets/1376749/14541626/dac474f4-0258-11e6-83f6-40e752028222.png)
+![layout examples](https://cloud.githubusercontent.com/assets/1376749/14541626/dac474f4-0258-11e6-83f6-40e752028222.png)
 
 ## [Installation and Setup](https://mmistakes.github.io/minimal-mistakes/docs/quick-start-guide/) / [Preview the Theme](https://mmistakes.github.io/minimal-mistakes/)