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="ALUMINIUM.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="832" ns="6" title="File:222730 screenshots 2013-05-21 00001.jpg" />
      <page pageid="408" ns="6" title="File:AGATE.png" />
      <page pageid="167" ns="6" title="File:AGAVE LARGE.png" />
      <page pageid="166" ns="6" title="File:AGAVE MEDIUM.png" />
      <page pageid="165" ns="6" title="File:AGAVE SMALL.png" />
      <page pageid="285" ns="6" title="File:ALCHEMIST.png" />
      <page pageid="854" ns="6" title="File:ALCHEMIST COMPLETED.jpg" />
      <page pageid="184" ns="6" title="File:ALOE VERA LARGE.png" />
      <page pageid="183" ns="6" title="File:ALOE VERA MEDIUM.png" />
      <page pageid="182" ns="6" title="File:ALOE VERA SMALL.png" />
    </pages>
  </query>
</api>