Oh an another optimization could be to instead of using a full image per frame, you could use smaller separated images, for example for characters, in the SpriteManager. Then use those sprites with Layered Images for composition.
Having a spritesheet of character images, per character, would also help in the future where you might want to make changes, or support different outfits or such in an already existing scene, without having to render the entire scene :)
Spritesheets will be especially useful for UI elements or other extra resources
https://renpy.org/doc/html/sprites.html
https://renpy.org/doc/html/layeredimage.html