This is one of the recently released Game of Thrones Season 6 teasers that I worked on last year for Imaginary Forces (NY). Besides the flag and camera move, what you're seeing is all basically a still image that was brought to life through 2.5D compositing techniques.
I always say matte paintings are actually never finished by the matte painter, but by the compositor! This is certainly true here, because the studio completely took my matte painting apart (how it was built for animation) and rearranged it to suit the needs of the edit. See the full image below!
That this often happens, comes as a surprise to many, but it's just another day in the life of a working matte painter. The funny part is, what they rearranged it into, is very similar to the first version I delivered. ;)