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="Blue_egg_3.png" />
  </query-continue>
  <query>
    <allimages>
      <img name="Barn_eggs.jpg" timestamp="2013-06-13T20:06:03Z" url="http://www.backyardpoultry.com/wiki/images/Barn_eggs.jpg" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Barn_eggs.jpg" ns="6" title="File:Barn eggs.jpg" />
      <img name="Barnevelder.jpg" timestamp="2013-06-13T20:04:05Z" url="http://www.backyardpoultry.com/wiki/images/Barnevelder.jpg" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Barnevelder.jpg" ns="6" title="File:Barnevelder.jpg" />
      <img name="Barnevelder_pullet.JPG" timestamp="2013-06-13T20:02:00Z" url="http://www.backyardpoultry.com/wiki/images/Barnevelder_pullet.JPG" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Barnevelder_pullet.JPG" ns="6" title="File:Barnevelder pullet.JPG" />
      <img name="Belgian_bantam.png" timestamp="2013-10-04T20:19:03Z" url="http://www.backyardpoultry.com/wiki/images/Belgian_bantam.png" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Belgian_bantam.png" ns="6" title="File:Belgian bantam.png" />
      <img name="Belgian_female.png" timestamp="2013-10-05T15:03:48Z" url="http://www.backyardpoultry.com/wiki/images/Belgian_female.png" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Belgian_female.png" ns="6" title="File:Belgian female.png" />
      <img name="Black_pekin_female.png" timestamp="2013-10-05T05:26:19Z" url="http://www.backyardpoultry.com/wiki/images/Black_pekin_female.png" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Black_pekin_female.png" ns="6" title="File:Black pekin female.png" />
      <img name="Blue_bantam_australorp.JPG" timestamp="2013-06-27T10:31:11Z" url="http://www.backyardpoultry.com/wiki/images/Blue_bantam_australorp.JPG" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Blue_bantam_australorp.JPG" ns="6" title="File:Blue bantam australorp.JPG" />
      <img name="Blue_crested_polish.png" timestamp="2013-10-05T11:18:48Z" url="http://www.backyardpoultry.com/wiki/images/Blue_crested_polish.png" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Blue_crested_polish.png" ns="6" title="File:Blue crested polish.png" />
      <img name="Blue_egg_1.png" timestamp="2013-10-03T23:48:48Z" url="http://www.backyardpoultry.com/wiki/images/Blue_egg_1.png" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Blue_egg_1.png" ns="6" title="File:Blue egg 1.png" />
      <img name="Blue_egg_2.png" timestamp="2013-10-03T23:49:09Z" url="http://www.backyardpoultry.com/wiki/images/Blue_egg_2.png" descriptionurl="http://www.backyardpoultry.com/wiki/index.php/File:Blue_egg_2.png" ns="6" title="File:Blue egg 2.png" />
    </allimages>
  </query>
</api>