well, you were right. i was trying to do as much of the sleuthing on my own as possible but now i've run out of ideas.
currently, the link I'm concerned about contains the image. additionally, the image file, the relevant img tag's height attribute, the link, and their containing div are all the same height. however, the vertical scrollbar still appears and i can scroll through about a millimeter of visually-blank space below the image.
the link is here: http://www.jamestbaker.com. below the "in the past" text, click on "cornell university" on the left. in the lower left of the 'popup' is the image that is scrolling unnecessarily.