DeprecationWarning: Image.Image.getdata is deprecated and will be removed in Pillow 14

[travishaagen]

slideshow.py:59: DeprecationWarning: Image.Image.getdata is deprecated and will be removed in Pillow 14 (2027-10-15). Use get_flattened_data instead.
  return max(strip.getdata()) < BLACK_THRESHOLD