You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information.
<?xml version="1.0"?>
<api>
  <query-continue>
    <allimages gaicontinue="000.carter.gif" />
  </query-continue>
  <query>
    <pages>
      <page pageid="139235" ns="6" title="File:&#039;Jewish Dance&#039; by Alexandr Onishenko, 1999.jpg" />
      <page pageid="93272" ns="6" title="File:-0exoplanet-final-browse.jpg" />
      <page pageid="129273" ns="6" title="File:-Comedy and tragedy masks.png" />
      <page pageid="49739" ns="6" title="File:0-picture.jpg" />
      <page pageid="75510" ns="6" title="File:0.jpg" />
      <page pageid="74681" ns="6" title="File:00-main.jpg" />
      <page pageid="94299" ns="6" title="File:000-Burris-Courtesy-225x300.gif" />
      <page pageid="94694" ns="6" title="File:000-George Pataki.jpg" />
      <page pageid="93274" ns="6" title="File:000.480px-Xlarge web.jpg" />
      <page pageid="87461" ns="6" title="File:000.Brewer.jpg" />
    </pages>
  </query>
</api>