在日志HTML编辑模式下，加入如下代码：

<DIV style="FILTER: Dropshadow(color=#cccccc,offX=4,offY=4); OVERFLOW: visible; WIDTH: 615px; HEIGHT: 465px">
<DIV style="BORDER-RIGHT: #999 1px solid; BORDER-TOP: #999 1px solid; BACKGROUND: white; FLOAT: left; OVERFLOW: visible; BORDER-LEFT: #999 1px solid; WIDTH: 10px; LINE-HEIGHT: 4px; BORDER-BOTTOM: #999 1px solid; LETTER-SPACING: 4px; HEIGHT: 10px">
<DIV style="BORDER-RIGHT: #ffffff 4px solid; BORDER-TOP: #ffffff 4px solid; BACKGROUND: white; OVERFLOW: visible; BORDER-LEFT: #ffffff 4px solid; WIDTH: 10px; LINE-HEIGHT: 4px; BORDER-BOTTOM: #ffffff 4px solid; LETTER-SPACING: 4px; HEIGHT: 10px"><IMG src="http://blufiles.storage.live.com/y1pQGY5wIUf_A4AjGVeorOsr-cF9hf4DjE-ejN29pscNPBsfTXsl5db8g65nNe0Ez2JQEhAKFQm0rU" height=450 width=600></DIV></DIV></DIV>

然后将蓝色处替换为你自己的图片地址即可

效果图：