title: Can html5 poster size be varied for use as small thumbnail?
body: <p>I want to use the html5 video poster attribute to set up a thumbnail for a video on a Joomla page. I'm using this markup:</p>
  
  <pre><code>&lt;video width="100%" height="100%" poster="/templates/beez_20/images/ws_wst2.png" controls&gt; 
  &lt;source src="/templates/beez_20/video/ws_wst2.webm" type='video/webm;codecs="vp8, vorbis"'/&gt;
        &lt;/video&gt;
  </code></pre>
  
  <p>This works OK but the poster image displayed at the same size as the video which defeats the purpose of having a thumbnail. The SO page, "How to set the thumbnail image on HTML5 video?", is on the topic, but doesn't address the thumbnail size issue. I don't know whether this is achievable using the poster attribute or not. I'm happy to use js or jquery if necessary. Any help would be much appreciated. </p>