add img pagination support of infinite scroll

searx/static/plugins/js/infinite_scroll.js

         if ($(document).height() - win.height() == win.scrollTop()) {
             var formData = $('#pagination form:last').serialize();
             if (formData) {
+                var pageno = $('#pagination input[name=pageno]:last').attr('value');
                 $('#pagination').html('<div class="loading-spinner"></div>');
                 $.post('./', formData, function (data) {
+                    var lastImageHref = $('.result-images:last a').attr('href');
                     var body = $(data);
+                    $('a[href^="#open-modal"]:last').attr('href', '#open-modal-1-' + pageno);
+                    body.find('.modal-image a:first').attr('href', lastImageHref);
                     $('#pagination').remove();
                     $('#main_results').append('<hr/>');
                     $('#main_results').append(body.find('.result'));