window.addEventListener('DOMContentLoaded', function() {
    for (var i=0; i<picture.length; i++) { 
       picture[i].addEventListener('click', function() {
	bigPicture.classList.remove('hidden');
         });
     }
});window.addEventListener('load', function() {
    for (var i=0; i<picture.length; i++) { 
       picture[i].addEventListener('click', function() {
	bigPicture.classList.remove('hidden');
         });
     }
});