supertux/data/images/objects/keys/key_wood.sprite

(supertux-sprite
 (action
  (name "default")
  (images "wood.png")
 )
 (action
  (name "display")
  (images "wood_display.png")
 )
 (action
  (name "outline")
  (images "l_outline.png")
 )               
)