title: Get image dpi for tif files using Pillow
body: <p>How to get tiff image DPI using pillow? Cant see in <a href="http://pillow.readthedocs.org/en/latest/reference/Image.html" rel="noreferrer">documentation</a>.</p>
  
  <pre><code>from PIL import Image
  im = Image.open('test.tif')
  print("im dpi?")
  </code></pre>