new_contents: import os, os.path
  import shutil
  from datetime import datetime
  import sys
  
  def do_folder(src_folder):
      assert os.path.isdir(src_folder)
      dst_folder = os.path.join(src_folder, 'timestamp_prefixed')
      print 'Input dir: %s'%src_folder
      print 'Output dir: %s'%dst_folder
      if not os.path.exists(dst_folder):
          print 'Creating %s' %dst_folder
          os.makedirs(dst_folder)
      for f in os.listdir(src_folder):
          base,ext = os.path.splitext(f)
          src_file = os.path.join(src_folder, f)
          if os.path.isfile(src_file) and ext.lower() == '.png':
              ctime = os.path.getctime(src_file)
              dt = datetime.utcfromtimestamp(ctime)
              dst_file = os.path.join(dst_folder, dt.strftime("%Y_%m_%d_")+f)
              print '%s ---> %s' % (src_file,dst_file)
              shutil.copyfile(src_file,dst_file)
  
  if __name__ == '__main__':
      folders = sys.argv[1:]
      if len(folders) == 0:
          do_folder('.')
      else:
          for f in folders:
              do_folder(f)
  
  
subject: Add script to create copies of PNG files w/ filenames prefixed with their creation time (Windows only)