Code "use strict"; let pic1 = new Image(); let pic2 = new Image(); let pic3 = new Image(); let pic4 = new Image(); pic1.src = '../images/th_musicCat.jpg'; pic2.src = '../images/th_computerCat.jpg'; pic3.src = '../images/th_phoneCat.jpg'; pic4.src = '../images/th_attackCat.jpg'; window.onload = function() { let elem1 = document.getElementById('r1'); let elem2 = document.getElementById('r2'); elem1.src = pic2.src; elem2.src = pic4.src; elem1.onmouseover = function() { elem1.src = pic1.src; }; elem1.onmouseout = function() { elem1.src = pic2.src; }; elem2.onmouseover = function() { elem2.src = pic3.src; }; elem2.onmouseout = function() { elem2.src = pic4.src; }; };