The png images in this directory are from:
  https://openclipart.org/detail/170302/vector-basketball
  https://openclipart.org/detail/5451/basketball-rim
  (public domain, https://openclipart.org/share )

Note that you could also put them inside "data" subdirectory.
Loading them using the 'castle-data:/my_image.png'
will automatically look inside "data" subdirectory,
if it exists.
