Can't center image
===

cannot center a image in a div. How can i center the image given inside the <div><a>

html code is as follows:

    <div id='post-area' style='background:#000; padding:20px 0;'>
    <a class='fancybox' rel='group' href='example-big.png'>
    <img src='example.png'  />
    </a>
    </div>

css code is as follows

    #post-area
    {
	font-size:13px;
	color:#000;
	text-align:left;
	width:450px;
	height:auto;
	font-family:Meera
	clear:both;
	margin-top:20px;
	letter-spacing:normal;
        }
        #post-area img
        {
	max-width:250px;
	height:auto;
	float:none;
	margin:0 auto;
	
       }
If there is any way to do this