.clearfix img { vertical-align: middle; }

button.prev, button.next {
background: url("../img/arrow-nav.png") no-repeat scroll left 0 rgba(0, 0, 0, 0);
display: block;
height: 23px;
position: absolute;
top: 320px;
width: 28px;
}
button.next{
    background-position: right 0;
    right: 60px;
}
button.prev {
    left: 60px;
}