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="20181121155730|Izvir_Sv._Vida.jpg" />
  </query-continue>
  <query>
    <allimages>
      <img name="Gold_Rock_Beach.jpg" timestamp="2019-02-18T12:17:32Z" user="Mirjamk" url="https://wiki.potnik.si/images/d/d9/Gold_Rock_Beach.jpg" descriptionurl="https://wiki.potnik.si/Slika:Gold_Rock_Beach.jpg" ns="6" title="Slika:Gold Rock Beach.jpg" />
      <img name="CocoCay.jpg" timestamp="2019-02-18T12:15:14Z" user="Mirjamk" url="https://wiki.potnik.si/images/b/b4/CocoCay.jpg" descriptionurl="https://wiki.potnik.si/Slika:CocoCay.jpg" ns="6" title="Slika:CocoCay.jpg" />
      <img name="Blue_Lagoon.jpeg" timestamp="2019-02-18T12:13:02Z" user="Mirjamk" url="https://wiki.potnik.si/images/9/97/Blue_Lagoon.jpeg" descriptionurl="https://wiki.potnik.si/Slika:Blue_Lagoon.jpeg" ns="6" title="Slika:Blue Lagoon.jpeg" />
      <img name="Mount_Alvernia.jpg" timestamp="2019-02-18T12:10:13Z" user="Mirjamk" url="https://wiki.potnik.si/images/4/45/Mount_Alvernia.jpg" descriptionurl="https://wiki.potnik.si/Slika:Mount_Alvernia.jpg" ns="6" title="Slika:Mount Alvernia.jpg" />
      <img name="Green_Turtle_Cay.jpg" timestamp="2019-02-18T12:04:35Z" user="Mirjamk" url="https://wiki.potnik.si/images/1/19/Green_Turtle_Cay.jpg" descriptionurl="https://wiki.potnik.si/Slika:Green_Turtle_Cay.jpg" ns="6" title="Slika:Green Turtle Cay.jpg" />
      <img name="bahami-sonci-vzhod.jpg" timestamp="2019-02-18T12:00:50Z" user="Mirjamk" url="https://wiki.potnik.si/images/c/c0/bahami-sonci-vzhod.jpg" descriptionurl="https://wiki.potnik.si/Slika:bahami-sonci-vzhod.jpg" ns="6" title="Slika:bahami-sonci-vzhod.jpg" />
      <img name="Bukovniško_jezero,_ribiška.jpg" timestamp="2018-11-21T16:00:05Z" user="MarkoPotnik" url="https://wiki.potnik.si/images/9/9d/Bukovni%C5%A1ko_jezero%2C_ribi%C5%A1ka.jpg" descriptionurl="https://wiki.potnik.si/Slika:Bukovni%C5%A1ko_jezero,_ribi%C5%A1ka.jpg" ns="6" title="Slika:Bukovniško jezero, ribiška.jpg" />
      <img name="Tropski_vrt.jpg" timestamp="2018-11-21T15:59:36Z" user="MarkoPotnik" url="https://wiki.potnik.si/images/f/f8/Tropski_vrt.jpg" descriptionurl="https://wiki.potnik.si/Slika:Tropski_vrt.jpg" ns="6" title="Slika:Tropski vrt.jpg" />
      <img name="Pustolovski_park.jpg" timestamp="2018-11-21T15:59:02Z" user="MarkoPotnik" url="https://wiki.potnik.si/images/c/cd/Pustolovski_park.jpg" descriptionurl="https://wiki.potnik.si/Slika:Pustolovski_park.jpg" ns="6" title="Slika:Pustolovski park.jpg" />
      <img name="Kapelica_Sv._Vida.jpg" timestamp="2018-11-21T15:58:17Z" user="MarkoPotnik" url="https://wiki.potnik.si/images/9/93/Kapelica_Sv._Vida.jpg" descriptionurl="https://wiki.potnik.si/Slika:Kapelica_Sv._Vida.jpg" ns="6" title="Slika:Kapelica Sv. Vida.jpg" />
    </allimages>
  </query>
</api>