document.div.style.background = 'url(second_1.jpg) no-repeat';

function new_art() {
   document.div.style.background = 'url(second_1.jpg)';
}

div {
  background: url(first_1.jpg) no-repeat;
  width: 15%;
  height: 87%;
}
div:hover {
  background: url(first_2.jpg);
}

<div></div>
<input type="button" value="Tap me!" onclick="new_art()">