new_contents: import os
  import string
  
  IMAGE_DIR = "images"
  
  for ch in string.ascii_lowercase:
      command = "tar cvzf images_%s.tar.gz %s/{%s,%s}*/*" \
          % (ch, IMAGE_DIR, ch, ch.upper())
      print(command)
      os.system(command)
  
subject: Add compress_images.py