admin, before submitting issue, I guess you have to walk-through whole website article elements, and then decide whether to give issue or not.

I will give you the steps, on how i could not, and could find all the images:
1. I made xpath search over the article on images and found only 35 images overall
2. I made search on javascript elements of the article to search for json or xml sources of images, but unfortunately, there were not traces of that
3. Then i thought, may be it is related to asynchronous request, so I clicked on the gallery and started tracking network packets. Finally i could find the path of the 64 images that you have said:
https://www.zmones.lt/ajax/gallery/e5ac397a-94c9-11e8-9f90-aa000054c883
All images meta data is asynchronously received as json file from the above link. And you were right, there were exactly 64 images with descriptions and dimensions and all image related metadata.
4. I also searched for other sources of this article and found the following link: https://www.15min.lt/vardai/naujiena/lietuva/atidarytas-festivalis-serseliafam-kino-moterimi-tapo-k-sereikaite-publikos-simpatija-g-zickyte-1050-717738#_
There is also gallery and they also do not store more than 50 images on their DOM. There is gallery-modal-js component that has hook on the click of the user to make xhr request and show all images as slideshow. By the way, same principle works on this article too:
https://www.zmones.lt/naujiena/atidarytas-festivalis-serseliafam-kino-moterimi-tapo-k-sereikaite-publikos-simpatija-g-zickyte.071423d7-9ae0-11e8-9f90-aa000054c883#

Please admin, can you clarify your question? How can i make a XHR (XMLHttpRequest) request from IV language? Or maybe you admin added some capability to make requests from language with help of third party libraries?

I hope and believe that IV language is only for parsing web-site.