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

(supertux-sprite
 (action
  (name "default")
  (images "water.png")
 )
 (action
  (name "display")
  (images "water_display.png")
 )
 (action
  (name "outline")
  (images "k_outline.png")
 )               
)