I am trying to create a layout where the vertical spacing between divs is pixel perfect. So far I\'ve ruled out almost all the big grid systems (960.gs, Blueprint), because
The vertical-align: baseline
is causing the gap at the bottom of your images.
In Strict doctypes, images are inline elements and behave like text. Aligning inline elements at the baseline causes them to leave room for text descenders even if there is not any text.
Adding img { vertical-align: bottom }
to your reset stylesheet will fix the problem.