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="Capitalist_mentality.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="283" ns="6" title="File:2011-08-13 Guerrilla gardened papayas on wasteland.jpg" />
      <page pageid="282" ns="6" title="File:2011-08-13 Pair of Guerilla gardened papayas in Dhaka, Bangladesh.jpg" />
      <page pageid="78" ns="6" title="File:Amish barn raising.jpg" />
      <page pageid="28" ns="6" title="File:Annalakshmi.jpg" />
      <page pageid="104" ns="6" title="File:Bailouts.jpg" />
      <page pageid="249" ns="6" title="File:Bankers.jpg" />
      <page pageid="79" ns="6" title="File:Barn raising depiction.jpg" />
      <page pageid="270" ns="6" title="File:BrokenLink.png" />
      <page pageid="103" ns="6" title="File:Buffalo Sisters Gift Circle March 2010.jpg" />
      <page pageid="63" ns="6" title="File:Capitalist.jpg" />
    </pages>
  </query>
</api>