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="20161124141958|Palette_mare_corallo.jpg" />
  </query-continue>
  <query>
    <allimages>
      <img name="Sviluppo_prtale_Addendum.pdf" timestamp="2018-12-20T10:31:00Z" user="Mzilioli" url="http://sp7.irea.cnr.it/wiki/images/9/9e/Sviluppo_prtale_Addendum.pdf" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:Sviluppo_prtale_Addendum.pdf" ns="6" title="File:Sviluppo prtale Addendum.pdf" />
      <img name="Sviluppo_portale_Flusso.pdf" timestamp="2018-12-20T10:30:27Z" user="Mzilioli" url="http://sp7.irea.cnr.it/wiki/images/5/5e/Sviluppo_portale_Flusso.pdf" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:Sviluppo_portale_Flusso.pdf" ns="6" title="File:Sviluppo portale Flusso.pdf" />
      <img name="Utenti_widget_uso_30_12_2016.pdf" timestamp="2018-12-20T10:27:57Z" user="Mzilioli" url="http://sp7.irea.cnr.it/wiki/images/f/fd/Utenti_widget_uso_30_12_2016.pdf" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:Utenti_widget_uso_30_12_2016.pdf" ns="6" title="File:Utenti widget uso 30 12 2016.pdf" />
      <img name="Portale_Wiki.jpg" timestamp="2017-05-15T08:08:44Z" user="Mzilioli" url="http://sp7.irea.cnr.it/wiki/images/d/d5/Portale_Wiki.jpg" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:Portale_Wiki.jpg" ns="6" title="File:Portale Wiki.jpg" />
      <img name="RITMARE_Data_Portal_(v0.0)_-_catalogo_delle_risorse_1802016.xlsx" timestamp="2017-05-04T07:19:06Z" user="Mzilioli" url="http://sp7.irea.cnr.it/wiki/images/a/aa/RITMARE_Data_Portal_%28v0.0%29_-_catalogo_delle_risorse_1802016.xlsx" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:RITMARE_Data_Portal_(v0.0)_-_catalogo_delle_risorse_1802016.xlsx" ns="6" title="File:RITMARE Data Portal (v0.0) - catalogo delle risorse 1802016.xlsx" />
      <img name="Paola_squared.jpg" timestamp="2017-01-20T16:02:57Z" user="Cfugazza" url="http://sp7.irea.cnr.it/wiki/images/9/92/Paola_squared.jpg" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:Paola_squared.jpg" ns="6" title="File:Paola squared.jpg" />
      <img name="Barrastrumenti.png" timestamp="2017-01-16T15:15:41Z" user="Ritmare" url="http://sp7.irea.cnr.it/wiki/images/5/50/Barrastrumenti.png" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:Barrastrumenti.png" ns="6" title="File:Barrastrumenti.png" />
      <img name="Palette_allegra.jpg" timestamp="2016-11-24T14:22:21Z" user="Ritmare" url="http://sp7.irea.cnr.it/wiki/images/7/78/Palette_allegra.jpg" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:Palette_allegra.jpg" ns="6" title="File:Palette allegra.jpg" />
      <img name="Palette_autunnale.jpg" timestamp="2016-11-24T14:22:02Z" user="Ritmare" url="http://sp7.irea.cnr.it/wiki/images/6/6d/Palette_autunnale.jpg" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:Palette_autunnale.jpg" ns="6" title="File:Palette autunnale.jpg" />
      <img name="Palette_intensa.jpg" timestamp="2016-11-24T14:20:17Z" user="Ritmare" url="http://sp7.irea.cnr.it/wiki/images/6/65/Palette_intensa.jpg" descriptionurl="http://sp7.irea.cnr.it/wiki/index.php/File:Palette_intensa.jpg" ns="6" title="File:Palette intensa.jpg" />
    </allimages>
  </query>
</api>