title: Failing to get image with requests.get
body: <p>My goal is to compute the average brightness of an image displayed at the given url.</p>
  <pre><code>import requests
  from PIL import ImageStat, UnidentifiedImageError
  from PIL import Image as ImPIL
  
  def brightness(imgUrl):
      response = requests.get(imgUrl)
      try:
          img = ImPIL.open(response.raw)
          img = img.convert('L')
          stat = ImageStat.Stat(img)
          return stat.mean[0] # Average brightness of pixels in given image
      except UnidentifiedImageError:
          print(imgUrl)
  </code></pre>
  <p>The images I am using are paintings hosted on Wikidata/Wikimedia.
  Here are some of the URLs that trigger the exception:</p>
  <pre><code>http://commons.wikimedia.org/wiki/Special:FilePath/15-10-27-Els%20Quatre%20Gats-RalfR-WMA%202740a.jpg
  http://commons.wikimedia.org/wiki/Special:FilePath/Garrote%20vil%2C%20de%20Ram%C3%B3n%20Casas.jpg
  http://commons.wikimedia.org/wiki/Special:FilePath/La%20morfina%20%28Santiago%20Rusi%C3%B1ol%29.jpg
  http://commons.wikimedia.org/wiki/Special:FilePath/Ramon%20Casas%20-%20Over%20My%20Dead%20Body%20-%20Google%20Art%20Project.jpg
  </code></pre>
  <p>What am I missing ?</p>