title: Determining JPG quality in Python (PIL)
body: <p>I am playing around with PIL library in Python and I am wondering how do I determine quality of given JPG image.  I try to open JPG image do something to it and save it again in the its original quality.  Image.save let me determine the desired quality:  </p>
  
  <pre><code>im.save(name, quality = x)  
  </code></pre>
  
  <p>but I can't see any way to extract original one. For now I am just guessing and try to have an output file of the same size as input by doing binary search on 'quality' parameter but this is not acceptable long term solution :)<br>
  I also tried using: Image.info but most of my images don't have any useful information there (ex: 'adobe', 'icc_profile', 'exif', 'adobe_transform')<br>
  Help !</p>