title: Take an image directory and resize all images in the directory
body: <p>I am trying to convert high resolution images to something more manageable for machine learning. Currently I have the code to resize the images to what ever height and width I want however I have to do one image at a time which isn't bad when I'm only doing a 12-24 images but soon I want to scale up to do a few hundred images. 
  I am trying to read in a directory rather than individual images and save the new images in a new directory. Initial images will vary from .jpg, .png, .tif, etc. but I would like to make all the output images as .png like I have in my code. </p>
  
  <pre><code>import os
  from PIL import Image
  
  filename = "filename.jpg"
  size = 250, 250
  file_parts = os.path.splitext(filename)
  
  outfile = file_parts[0] + '_250x250' + file_parts[1]
  try:
      img = Image.open(filename)
      img = img.resize(size, Image.ANTIALIAS)
      img.save(outfile, 'PNG')
  except IOError as e:
      print("An exception occured '%s'" %e)
  </code></pre>
  
  <p>Any help with this problem is appreciated.</p>