title: How to download this GIF(dynamic) by Python?
body: <p>I give an url as example:</p>
  <pre><code>imgurl = &quot;http://ww4.sinaimg.cn/large/a7bf601fjw1f7jsbj34a1g20kc0bdnph.gif&quot;
  </code></pre>
  <p>You can see it in your browser.</p>
  <p>Now I want to download it. I <strong>have tried</strong>:</p>
  <pre><code>urllib.urlretrieve(imgurl, filepath)
  </code></pre>
  <p>failed, got an &quot;error&quot; picture.</p>
  <pre><code>wget.download(imgurl)
  </code></pre>
  <p>failed, got an &quot;error&quot; picture.</p>
  <pre><code>r = requests.get(imgurl, stream=True)
  img = PIL.Image.open(StringIO(r.content))
  img.save(filepath)
  </code></pre>
  <p>failed, got a static picture, I mean, just one frame.</p>
  <p><strong>So what should I do?</strong></p>