renpy/doc/cookbook/Initializing Images Mini-Engine

From Ren'Py Visual Novel Engine

Copy and paste this into your script.rpy at the top.

init:
  #gfx initializer
  python:
    import os
    for fname in os.listdir(config.gamedir + '/gfx'):
      if fname.endswith(('.jpg', '.png')):
        tag = fname[:-4]
        fname =  'gfx/' + fname
      renpy.image(tag, fname)