The image is floating (it has float: right;) so it isn’t calculated in the height of the containing div.
You should either add a div or span with clear:both at the end of the containing div or add a <br clear=“all” /> at the end of the containing div.
Note: I copy/pasted this from FireBug, the HTML itself probably doesn’t say rgb(192, 192, 192) but some hexadecimal value. FireBug tends to rewrite those to rgb. Dunno why.