title: How long is Facebook caching the sharing thumbnails?
body: <p>How long is Facebook caching the sharing thumbnails? I've added a custom thumbnail for my page using:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;meta property="og:image" content="/path/to/my/image" /&gt;
  </code></pre>
  
  <p>But on pages my previous image is displayed => it is cached somewhere on FB servers.</p>
  
  <p>Any ideas how to flush that cache or how long does it take once FB loads a new image?</p>