Next time, please thumb your images please. There isn't a surefire way of doing this except for DIV layering.
CODE
<style type="text/css">
.picture {position:absolute; margin-top:XXXpx; margin-left:XXXpx; left:50%; width:XXXpx; height:XXXpx; z-index:2;}
</style>
<div class="picture">
<img src="IMAGEURLHERE" />
</div>
Just play around with margins until you get what you want.