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>
    <pages>
      <page pageid="1" ns="0" title="Main Page">
        <images>
          <im ns="6" title="File:435048950 1422960068589042 6684458865674116809 n.jpg" />
          <im ns="6" title="File:435066478 927977502360267 6679138981589265670 n.jpg" />
          <im ns="6" title="File:435077181 1461128924479445 7312769958814895200 n.jpg" />
          <im ns="6" title="File:439021315 1200058320963978 8495498374226392471 n.jpg" />
          <im ns="6" title="File:441015130 787443890019687 6587241493291958201 n.jpg" />
          <im ns="6" title="File:441015275 967490141134794 1727313023740350039 n.jpg" />
          <im ns="6" title="File:6d619c1a-9a2a-460e-a625-bd193f40933b RETINA PORTRAIT 3 2.jpg" />
        </images>
      </page>
    </pages>
  </query>
</api>