CSS image centering issue

the margins in this style in style.css of your theme:

#contentarchive .postarea img {

	display: block;

	background: #EEEEEE;

	padding: 3px;

	margin: 0px 0px 10px 0px;

	border: 1px solid #DDDDDD;

	}

are overwriting the margins in the img.aligncenter style.

remove this line from the above:

margin: 0px 0px 10px 0px;