The images you have seen were composed by editing photos taken with a
digital camera in front of a blue wall (thanks to the deranged interior
decorators who painted the Union for that one...) and inserted into stills
from the movie which were edited with GIMP.
Some sample shots before and after editing...
And a few other stills that were used at some point...
And finally a sample blue screen shot...
And in case you're wondering, it is a lot harder than it looks...