title: Use Regular Expression to retrieve Url in the row with more than one Url
body: <p>This is an example string.</p>
  
  <pre><code>&lt;p style="text-align: center;"&gt;&lt;a href="http://www.evangelical-library.org.uk" target="_blank"&gt;&lt;img class="aligncenter wp-image-22582 size-full" src="http://the7.dream-demo.com/main/wp-content/uploads/sites/9/2014/05/show-04.png" alt="" width="372" height="225" /&gt;&lt;/a&gt;&lt;/p
  </code></pre>
  
  <p>There are <code>two Url in a row</code></p>
  
  <p>One is for PNG, the other is for a web page. I want to get the Png url like the pattern "http:.....png".</p>
  
  <p>It simply uses <code>"http://.*?png"</code>, but it retrieves a string from the first <code>"http://"</code> URL to <strong>the second Url with Png file extension</strong>.</p>
  
  <p>I can now do it using the condition <code>href and src</code> to identify which belongs to <code>Png url</code>. But it will miss a lot of png urls with other patterns like <code>&lt;png&gt;Png url&lt;/png&gt;</code>.</p>
  
  <p><strong>How could it be solved?</strong> Thanks.</p>