At the end of The Hunger Games Katniss and Peeta were the victors in the annual Hunger Games. As Catching Fire begins they must go on the victory tour, visiting each of the Districts to show the Capitol's magnaminous gesture towards DIstrict XII. These teaser posters for the movie sell that concept, using a new Soviet agitprop style to get the message across.
I quite liked The Hunger Games, and I'm looking forward to Catching Fire... although the hiring of Francis Lawrence as director makes me very, very worried. Very worried indeed.