Scrape image downloaded from javascript button

I would like to scrape a website hosting images.

Ultimately, the images are downloaded with a download button, which has an onclick method like this:

function downloadPhoto() {
        data = {  };
        data.directory_id = '59125';
        data.fileName = '_23113.JPG';
        $.ajax({
            url: '/photo/request-link',
            data: data,
            type: 'post',
            dataType: 'json',
            async: false,
            success: function (response) {
                if (response.state == 'TRUE') {
                    window.open('/photo/download');
                }
                else {
                    $('div#alert').html(response.message);
                    $('div#alert').dialog({ })
                }
            }
        })
    }

Sitemap:

{"_id":"metryki-genbaza","startUrl":["https://metryki.genbaza.pl/index/list"],"selectors":[{"id":"county","parentSelectors":["_root"],"type":"SelectorLink","selector":".nav-list a","multiple":true,"delay":0},{"id":"city","parentSelectors":["county"],"type":"SelectorLink","selector":".nav-list a","multiple":true,"delay":0},{"id":"docset","parentSelectors":["city"],"type":"SelectorLink","selector":".nav-list a","multiple":true,"delay":0},{"id":"doc","parentSelectors":["docset"],"type":"SelectorLink","selector":".span9 a","multiple":true,"delay":0},{"id":"download","parentSelectors":["doc"],"type":"SelectorPopupLink","selector":"button[onclick]","multiple":false,"delay":0},{"id":"county-name","parentSelectors":["doc"],"type":"SelectorText","selector":".breadcrumb li:nth-of-type(2) a","multiple":false,"delay":0,"regex":""},{"id":"city-name","parentSelectors":["doc"],"type":"SelectorText","selector":".breadcrumb li:nth-of-type(3) a","multiple":false,"delay":0,"regex":""},{"id":"docset-name","parentSelectors":["doc"],"type":"SelectorText","selector":".breadcrumb li:nth-of-type(4) a","multiple":false,"delay":0,"regex":""},{"id":"doc-num","parentSelectors":["doc"],"type":"SelectorText","selector":"ul.breadcrumb","multiple":false,"delay":0,"regex":""}]}

How can I scrape the image data?