The poster shows Superman (Henry Cavill) in handcuffs, being led down a hallway by a team of soldiers. One has to assume that he is being lead willingly, because those cuffs really don’t look all that strong.
As a comic fan, one has to wonder if the appearance of both the military and a number of Kryptonians means that the plot for the film was inspired by the “New Krypton/War of the Superman” arc which ran in the comics from 2008-2010. In that story, Superman is caught in a war between a group of Kryptonian survivors led by General Zod and the governments of the Earth. As far as I can remember, Superman wasn’t arrested during that story arc, but neither side was too happy with him.
The Man of Steel is set to be released on June 14, 2013.