Add Scrollbars to Image Popup Windows in Movable Type 4

I post a lot of thumbnail images on Consuming Louisville that link to very large full size images. By default Movable Type doesn't add scrollbars or allow resizing for the popup windows created for images. That's a problem because those large images of mine get cut off with no way to expand the window or scroll to see the rest of the image. So of course I needed to turn on scrollbars and turn on...