Apparently, he was at the Blizzard summit for the press.
The photos were published in the World of Warcraft section on Reddit. Judging by the frames, the short film will be devoted to meeting Saurfang with Thrall. He probably wants to make him the new leader of the Horde.
Thus, one fan theories can be confirmed.
When the short film will be shown to everyone, is still unknown. Usually Blizzard does not tie the output of the clips to E3, and it will not be on Games с 2019. Based on this, the video may appear at any time.