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 aistart="2011-08-06T02:03:15Z" />
  </query-continue>
  <query>
    <allimages>
      <img name="Screenshot-csw-output.png" timestamp="2016-10-05T19:18:43Z" user="StefanS" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/8/87/Screenshot-csw-output.png" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:Screenshot-csw-output.png" ns="6" title="File:Screenshot-csw-output.png" />
      <img name="Pyp_uml.jpg" timestamp="2014-09-05T15:54:27Z" user="StefanS" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/a/a0/Pyp_uml.jpg" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:Pyp_uml.jpg" ns="6" title="File:Pyp uml.jpg" />
      <img name="Pyp_architecture.jpg" timestamp="2014-09-05T15:54:16Z" user="StefanS" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/3/33/Pyp_architecture.jpg" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:Pyp_architecture.jpg" ns="6" title="File:Pyp architecture.jpg" />
      <img name="CEDEUS_Detailed_Architecture_with_GeoNode_-_single_db.png" timestamp="2013-12-20T20:15:25Z" user="Mentaer" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/b/b0/CEDEUS_Detailed_Architecture_with_GeoNode_-_single_db.png" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:CEDEUS_Detailed_Architecture_with_GeoNode_-_single_db.png" ns="6" title="File:CEDEUS Detailed Architecture with GeoNode - single db.png" />
      <img name="CEDEUS_Physical_Architecture-central.png" timestamp="2013-11-04T20:33:53Z" user="Mentaer" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/f/f0/CEDEUS_Physical_Architecture-central.png" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:CEDEUS_Physical_Architecture-central.png" ns="6" title="File:CEDEUS Physical Architecture-central.png" />
      <img name="CEDEUS_Physical_Architecture-multi-server_decentral.png" timestamp="2013-11-04T20:28:43Z" user="Mentaer" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/5/5d/CEDEUS_Physical_Architecture-multi-server_decentral.png" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:CEDEUS_Physical_Architecture-multi-server_decentral.png" ns="6" title="File:CEDEUS Physical Architecture-multi-server decentral.png" />
      <img name="Dataenrichment_v4_150g.jpg" timestamp="2013-08-09T15:14:29Z" user="Mentaer" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/2/27/Dataenrichment_v4_150g.jpg" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:Dataenrichment_v4_150g.jpg" ns="6" title="File:Dataenrichment v4 150g.jpg" />
      <img name="Wyp_screenshot.png" timestamp="2013-08-09T15:07:59Z" user="Mentaer" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/8/88/Wyp_screenshot.png" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:Wyp_screenshot.png" ns="6" title="File:Wyp screenshot.png" />
      <img name="Ojhorae.jpg" timestamp="2013-08-09T14:55:46Z" user="Mentaer" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/1/1d/Ojhorae.jpg" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:Ojhorae.jpg" ns="6" title="File:Ojhorae.jpg" />
      <img name="Stefan_puerto_madryn_small.jpg" timestamp="2011-08-06T02:29:57Z" user="Mentaer" url="http://wiki.geosteiniger.cl/mediawiki-1.22.7/images/d/dd/Stefan_puerto_madryn_small.jpg" descriptionurl="http://wiki.geosteiniger.cl/mediawiki-1.22.7/index.php/File:Stefan_puerto_madryn_small.jpg" ns="6" title="File:Stefan puerto madryn small.jpg" />
    </allimages>
  </query>
</api>