You are looking at the HTML representation of the XML format.
HTML is good for debugging, but probably is not suitable for your application.
See complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allimages gaifrom="603 103.gif" />
  </query-continue>
  <query>
    <pages>
      <page ns="6" title="File:12.gif" missing="" />
      <page ns="6" title="File:15.gif" missing="" />
      <page ns="6" title="File:161.gif" missing="" />
      <page ns="6" title="File:22.gif" missing="" />
      <page ns="6" title="File:2313.gif" missing="" />
      <page ns="6" title="File:2323.gif" missing="" />
      <page ns="6" title="File:2333 4433.gif" missing="" />
      <page ns="6" title="File:2343.gif" missing="" />
      <page ns="6" title="File:323.gif" missing="" />
      <page ns="6" title="File:4434 8535.gif" missing="" />
    </pages>
  </query>
</api>