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 aicontinue="20110727160310|176_36_quest.jpg" />
  </query-continue>
  <query>
    <allimages>
      <img name="Icon_Sentinel_Level17.png" timestamp="2013-11-11T19:15:09Z" user="Quizzotto" url="images/xhodon_wiki_it/c/cc/Icon_Sentinel_Level17.png" descriptionurl="https://wiki.xhodon.it/File:Icon_Sentinel_Level17.png" ns="6" title="File:Icon Sentinel Level17.png" />
      <img name="Icon_Sentinel_Level16.png" timestamp="2013-11-11T19:15:01Z" user="Quizzotto" url="images/xhodon_wiki_it/5/51/Icon_Sentinel_Level16.png" descriptionurl="https://wiki.xhodon.it/File:Icon_Sentinel_Level16.png" ns="6" title="File:Icon Sentinel Level16.png" />
      <img name="Icon_Sentinel_Level15.png" timestamp="2013-11-11T19:14:51Z" user="Quizzotto" url="images/xhodon_wiki_it/1/1e/Icon_Sentinel_Level15.png" descriptionurl="https://wiki.xhodon.it/File:Icon_Sentinel_Level15.png" ns="6" title="File:Icon Sentinel Level15.png" />
      <img name="Icon_Sentinel_Level14.png" timestamp="2013-11-11T19:14:41Z" user="Quizzotto" url="images/xhodon_wiki_it/7/75/Icon_Sentinel_Level14.png" descriptionurl="https://wiki.xhodon.it/File:Icon_Sentinel_Level14.png" ns="6" title="File:Icon Sentinel Level14.png" />
      <img name="Icon_Sentinel_Level13.png" timestamp="2013-11-11T19:14:34Z" user="Quizzotto" url="images/xhodon_wiki_it/6/67/Icon_Sentinel_Level13.png" descriptionurl="https://wiki.xhodon.it/File:Icon_Sentinel_Level13.png" ns="6" title="File:Icon Sentinel Level13.png" />
      <img name="Icon_Sentinel_Level12.png" timestamp="2013-11-11T19:14:25Z" user="Quizzotto" url="images/xhodon_wiki_it/7/74/Icon_Sentinel_Level12.png" descriptionurl="https://wiki.xhodon.it/File:Icon_Sentinel_Level12.png" ns="6" title="File:Icon Sentinel Level12.png" />
      <img name="Icon_Sentinel_Level11.png" timestamp="2013-11-11T19:14:16Z" user="Quizzotto" url="images/xhodon_wiki_it/2/2d/Icon_Sentinel_Level11.png" descriptionurl="https://wiki.xhodon.it/File:Icon_Sentinel_Level11.png" ns="6" title="File:Icon Sentinel Level11.png" />
      <img name="Icon_Sentinel_Level10.png" timestamp="2013-11-11T19:13:52Z" user="Quizzotto" url="images/xhodon_wiki_it/d/d6/Icon_Sentinel_Level10.png" descriptionurl="https://wiki.xhodon.it/File:Icon_Sentinel_Level10.png" ns="6" title="File:Icon Sentinel Level10.png" />
      <img name="178_36_quest.jpg" timestamp="2011-07-27T16:03:44Z" user="Tiziano1990" url="images/xhodon_wiki_it/6/62/178_36_quest.jpg" descriptionurl="https://wiki.xhodon.it/File:178_36_quest.jpg" ns="6" title="File:178 36 quest.jpg" />
      <img name="177_36_quest.jpg" timestamp="2011-07-27T16:03:26Z" user="Tiziano1990" url="images/xhodon_wiki_it/c/ca/177_36_quest.jpg" descriptionurl="https://wiki.xhodon.it/File:177_36_quest.jpg" ns="6" title="File:177 36 quest.jpg" />
    </allimages>
  </query>
</api>