>>38259744OP Posted the image of Lumiose not the guy you were replying to, he didn't post any image.
What I mean by the key pose is the static image that was originally used in Gen 2-4 as what you'd see once the Pokemon's intro animation played out, the related image is Pikachu's key pose in Platinum for instance. While Pikachu isn't the best example for this several Pokemon's key poses in older generations are of them in more aggressive/action looking appearances, stuff like Nidoking's scowled face or Houndoom's raised back in the Gen 3 games.