Edit in JSFiddle

// 아코디언
<nav>
    <ul>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
    </ul>
</nav>

* {
  margin: 0;
  padding: 0;
}
ul,
ol {
  list-style-type: none;
}
li {
  width: 150px;
  height: 480px;
  float: right;
  transition: all .5s;
}
nav li:nth-child(1) {
  background: url(http://tympanus.net/Tutorials/ElegantAccordion/images/1.jpg) no-repeat center center;
}
nav li:nth-child(1):hover {
  width: 480px;
}
nav li:nth-child(2) {
  background: url(http://tympanus.net/Tutorials/ElegantAccordion/images/2.jpg) no-repeat center center;
}
nav li:nth-child(2):hover {
  width: 480px;
}
nav li:nth-child(3) {
  background: url(http://tympanus.net/Tutorials/ElegantAccordion/images/3.jpg) no-repeat center center;
}
nav li:nth-child(3):hover {
  width: 480px;
}
nav li:nth-child(4) {
  background: url(http://tympanus.net/Tutorials/ElegantAccordion/images/4.jpg) no-repeat center center;
}
nav li:nth-child(4):hover {
  width: 480px;
}