title: jQuery get img source attributes from list and push into array
body: <p>I have this thumbnail list and would like push the image paths (sources) into an array: tn_array</p>
  
  <pre><code>&lt;ul id="thumbnails"&gt;
      &lt;li&gt;&lt;img src="somepath/tn/004.jpg" alt="fourth caption" /&gt;&lt;/a&gt;&lt;/li&gt;
      &lt;li&gt;&lt;img src="somepath/tn/005.jpg" alt="fifth caption" /&gt;&lt;/a&gt;&lt;/li&gt;
      &lt;li&gt;&lt;img src="somepath/tn/006.jpg" alt="sixth caption" /&gt;&lt;/a&gt;&lt;/li&gt;
  &lt;/ul&gt;
  </code></pre>