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="Full_map_ex_4.png" />
  </query-continue>
  <query>
    <allimages>
      <img name="Breadcrumb.jpg" timestamp="2013-11-26T16:12:55Z" url="http://wiki.exploring-greece.gr/images/e/e1/Breadcrumb.jpg" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:Breadcrumb.jpg" ns="6" title="File:Breadcrumb.jpg" />
      <img name="Bulbgraph.png" timestamp="2013-11-26T12:19:21Z" url="http://wiki.exploring-greece.gr/images/6/60/Bulbgraph.png" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:Bulbgraph.png" ns="6" title="File:Bulbgraph.png" />
      <img name="Compact_tp_view.jpg" timestamp="2013-11-26T14:36:35Z" url="http://wiki.exploring-greece.gr/images/e/e6/Compact_tp_view.jpg" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:Compact_tp_view.jpg" ns="6" title="File:Compact tp view.jpg" />
      <img name="EG-Logo-white.png" timestamp="2013-10-15T15:37:08Z" url="http://wiki.exploring-greece.gr/images/b/b2/EG-Logo-white.png" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:EG-Logo-white.png" ns="6" title="File:EG-Logo-white.png" />
      <img name="Exploring_greece_logo.png" timestamp="2013-10-15T15:31:09Z" url="http://wiki.exploring-greece.gr/images/e/ee/Exploring_greece_logo.png" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:Exploring_greece_logo.png" ns="6" title="File:Exploring greece logo.png" />
      <img name="Full_map_area_600h.jpg" timestamp="2013-11-29T18:42:04Z" url="http://wiki.exploring-greece.gr/images/6/6a/Full_map_area_600h.jpg" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:Full_map_area_600h.jpg" ns="6" title="File:Full map area 600h.jpg" />
      <img name="Full_map_dynamic_600h.jpg" timestamp="2013-11-29T18:42:23Z" url="http://wiki.exploring-greece.gr/images/d/dc/Full_map_dynamic_600h.jpg" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:Full_map_dynamic_600h.jpg" ns="6" title="File:Full map dynamic 600h.jpg" />
      <img name="Full_map_ex_1.png" timestamp="2013-11-29T18:51:17Z" url="http://wiki.exploring-greece.gr/images/b/be/Full_map_ex_1.png" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:Full_map_ex_1.png" ns="6" title="File:Full map ex 1.png" />
      <img name="Full_map_ex_2.png" timestamp="2013-11-29T18:43:14Z" url="http://wiki.exploring-greece.gr/images/a/a1/Full_map_ex_2.png" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:Full_map_ex_2.png" ns="6" title="File:Full map ex 2.png" />
      <img name="Full_map_ex_3.png" timestamp="2013-11-29T18:43:32Z" url="http://wiki.exploring-greece.gr/images/c/c9/Full_map_ex_3.png" descriptionurl="http://wiki.exploring-greece.gr/index.php?title=File:Full_map_ex_3.png" ns="6" title="File:Full map ex 3.png" />
    </allimages>
  </query>
</api>