title: install pil on virtualenv with libjpeg
body: <p>Currently I'm installing PIL into my virtual env as follows:</p>
  
  <pre><code>pip install -E . -r ./releases/%s/requirements.txt
  </code></pre>
  
  <p>where requirements.txt contains:</p>
  
  <pre><code>pil
  </code></pre>
  
  <p>I can upload png images but not jpeg images currently.  From reading on the web it seems i may need libjpeg decoder?  Am i installing pil incorrectly?  What is the proper way to install pil for django in a virtual env with libjpeg?</p>