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="2007Shirt_Back.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1067" ns="6" title="File:1261VEX.JPG" />
      <page pageid="523" ns="6" title="File:2004Robot.jpg" />
      <page pageid="497" ns="6" title="File:2005Button.jpg" />
      <page pageid="860" ns="6" title="File:2005Shirt Back.jpg" />
      <page pageid="118" ns="6" title="File:2005 TeamPicture.jpg" />
      <page pageid="498" ns="6" title="File:2006Button.jpg" />
      <page pageid="550" ns="6" title="File:2006Shirt Back.jpg" />
      <page pageid="549" ns="6" title="File:2006Shirt Front.jpg" />
      <page pageid="119" ns="6" title="File:2006 TeamPicture.jpg" />
      <page pageid="494" ns="6" title="File:2007Button.jpg" />
    </pages>
  </query>
</api>