绝对定位错乱

<div class="navimgLeft clearfix">
	<div class="navimgLeftone">
		<div class="navimgLeftonebox">
			<img src="images/leftone.jpg">
			<img src="images/leftone.jpg">
			<img src="images/leftone.jpg">
			<img src="images/leftone.jpg">
			<img src="images/leftone.jpg">
		</div>
							
		<div class="button1">
			<a></a>
			<a></a>
			<a></a>
			<a></a>
			<a></a>
		</div>
        </div>
</div>
				
.navimgLeft{
	height:480px;
	width:520px;
	
	float:left;
}
/* 左上图片 */
.navimgLeft .navimgLeftone{
	height:280px;
	width:520px;
	overflow:hidden;
	display:relative;
}

.navimgLeftone .button1{
	position:absolute;
	height:5px;
	width:100%;
	left:50%;
	bottom:20px;
	 
}
.button1 a{
	display:inline-block;
	height:5px;
	width:20px;
	background:#000;
}