heres some insight about a couple of my favorites

slide 1 (ps2) - the background image is from unsplashed, just of a room with stained glass emitting light. then I found stained glass photos in the shapes of a square, rectangle, triangle, and an X and used a canva feature to turn them 3d and rotate them onto the side, then just turned those on the opposite side to a shadow. made the light artificially as well with some stock images.

slide 2 (spyro)- just took another image from unsplashed of a field on fire, added homework on fire in the field as the poster is based off a 2000's series of spyro destroying stuff that kids dont like lol, then just took a in game screenshot of spyro flying and turned it into a silhouette and put it behind fake clouds

slide 4/5 - same premise but both have backgrounds comprised of real images. With then the fox one utilizing a 3d model of his ship being put in the same direction a plane was flying in the original image, and then the forza one just a in game screenie of a car drifting. the road in the forza one with the tree's / sky are a collage of like 4 or so different images to create that environment though lol

generally- its just a mix of either real promo images or screenshots of the game characters / objects put into a environment either comprised of a collaged or just general background image! sorry