window.onload = () => {
   ...
}

var Load = () => {
   document.querySelectorAll('[data-target]').forEach((result) => {
      result.onclick = (e) => {
         document.querySelector(".modal-card-body").innerHTML = e.target.outerHTML;
         let modal = document.getElementById(result.getAttribute('data-target'))
         modal.classList.toggle("is-active")
         modal.querySelector('.delete').onclick = () => { modal.classList.toggle("is-active") }
      }
   })
}

document.querySelector(".modal-card-body").innerHTML = e.target.outerHTML;

var folder = "img/";
$.ajax({
   url: folder,
   success: function (data) {
      $(data).find("a").attr("href", function (i, val) {
         if (val.match(/.(jpe?g|png|gif)$/)) {
            $(".columns").append("<div class = 'column is-4' > <a data-toggle='modal' data-target = '#modal_name' class = 'img-input'> <img id = 'img-card' src='https://www.cleverfiles.com/howto/wp-content/uploads/2016/08/mini.jpg'></a></div>");
         }
         Load();
      });
   }
});