code: def list_all_image(path, valid_exts=VALID_IMAGE_EXTS):
      
      for filename in os.listdir(path):
          bname, ext = os.path.splitext(filename)
          if ext.lower() not in VALID_IMAGE_EXTS:
              continue
          filepath = os.path.join(path, filename)
          yield strutils.decode(filepath)
docs: List all images under path
  
      @return unicode list