TurnerIT,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
</style>
</head>
<body>
<div class="wrapper">
<div class="mainImg">
<img src="img/hot.jpg">
</div>
<div class="images">
<img src="img/Beautiful.jpg" alt="">
<img src="img/Curly.jpg" alt="">
<img src="img/Libr.jpg" alt="">
<img src="img/Redhead.jpg" alt="">
<img src="img/Winter.jpg" alt="">
</div>
</div>
<script>
var img = document.getElementsByClassName("images");
var selectImg;
img[0].onclick = function(event){
var target = event.target;
if(target.tagName != "IMG") return; //что и зачем вы тут творите, одному вам ведомо
var selectImg = document.createElement("div");
selectImg.className = "newImg";
selectImg.appendChild(target.cloneNode());
}
</script>
</body>
</html>