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="BanderaBarbanegra_NacentaI.jpg" />
  </query-continue>
  <query>
    <allimages>
      <img name="BIZCOCHO_CHOCO_IÑAKI.jpg" timestamp="2016-06-09T11:09:44Z" url="http://estudiopedia.org/images/5/52/BIZCOCHO_CHOCO_I%C3%91AKI.jpg" descriptionurl="http://estudiopedia.org/index.php?title=File:BIZCOCHO_CHOCO_I%C3%91AKI.jpg" ns="6" title="File:BIZCOCHO CHOCO IÑAKI.jpg" />
      <img name="BRUNO_MARS_CC.jpg" timestamp="2013-12-05T13:29:25Z" url="http://estudiopedia.org/images/c/c6/BRUNO_MARS_CC.jpg" descriptionurl="http://estudiopedia.org/index.php?title=File:BRUNO_MARS_CC.jpg" ns="6" title="File:BRUNO MARS CC.jpg" />
      <img name="BUEY_LOMO_ALTO_jp.JPG" timestamp="2016-06-02T12:06:36Z" url="http://estudiopedia.org/images/b/b4/BUEY_LOMO_ALTO_jp.JPG" descriptionurl="http://estudiopedia.org/index.php?title=File:BUEY_LOMO_ALTO_jp.JPG" ns="6" title="File:BUEY LOMO ALTO jp.JPG" />
      <img name="Bagels_delPinoM.jpg" timestamp="2015-04-20T12:05:21Z" url="http://estudiopedia.org/images/e/eb/Bagels_delPinoM.jpg" descriptionurl="http://estudiopedia.org/index.php?title=File:Bagels_delPinoM.jpg" ns="6" title="File:Bagels delPinoM.jpg" />
      <img name="Balanza-estropeada.jpg" timestamp="2014-03-28T12:03:35Z" url="http://estudiopedia.org/images/7/7c/Balanza-estropeada.jpg" descriptionurl="http://estudiopedia.org/index.php?title=File:Balanza-estropeada.jpg" ns="6" title="File:Balanza-estropeada.jpg" />
      <img name="Balanza2.jpg" timestamp="2014-03-28T12:06:27Z" url="http://estudiopedia.org/images/b/b9/Balanza2.jpg" descriptionurl="http://estudiopedia.org/index.php?title=File:Balanza2.jpg" ns="6" title="File:Balanza2.jpg" />
      <img name="Balanzaoro_Abellanp.jpg" timestamp="2015-05-05T12:23:26Z" url="http://estudiopedia.org/images/5/5f/Balanzaoro_Abellanp.jpg" descriptionurl="http://estudiopedia.org/index.php?title=File:Balanzaoro_Abellanp.jpg" ns="6" title="File:Balanzaoro Abellanp.jpg" />
      <img name="Ballena_y_glaciar.jpg" timestamp="2013-12-10T10:18:49Z" url="http://estudiopedia.org/images/5/55/Ballena_y_glaciar.jpg" descriptionurl="http://estudiopedia.org/index.php?title=File:Ballena_y_glaciar.jpg" ns="6" title="File:Ballena y glaciar.jpg" />
      <img name="Ballenas-jorobadas.jpg" timestamp="2015-06-15T13:03:37Z" url="http://estudiopedia.org/images/3/3b/Ballenas-jorobadas.jpg" descriptionurl="http://estudiopedia.org/index.php?title=File:Ballenas-jorobadas.jpg" ns="6" title="File:Ballenas-jorobadas.jpg" />
      <img name="Ballenasgrandes.jpeg" timestamp="2015-06-15T13:15:25Z" url="http://estudiopedia.org/images/8/8a/Ballenasgrandes.jpeg" descriptionurl="http://estudiopedia.org/index.php?title=File:Ballenasgrandes.jpeg" ns="6" title="File:Ballenasgrandes.jpeg" />
    </allimages>
  </query>
</api>