http://msdn.microsoft.com/en-US/office/dn448479
The first thing I noticed was the nice metro style tiles on the landing page that even changes colour in accordance to the sites theme. I wanted to know how to add my own, so I started fiddling and found a hidden Promoted Links list called GettingStarted.
I merely added my own entry to the Promoted Links list.
Note: If you give your image a transparent background it will use the colour of the current theme.
All Promoted Links lists have a metro view by default, you can create your own by adding the Promoted Links app to your site, it can be found under Site Contents > Your Apps > Promoted Links.
