those are the actual sizes of the images, not the desired size
<div id="main">
<h1>Pictures</h1>
<img width='594' height='292' alt='alt text is a requirement' src="Pictures/3DIM_poster.jpg" />
Poster presentation at 3DIM 2009.
<img width='594' height='612' alt='alt text is a requirement' src="Pictures/scanner_inside.jpg" />
Leica HDS3000 LiDAR scanner in the lab.
<img width='594' height='612' alt='alt text is a requirement' src="Pictures/scanner_outside.jpg" />A day of scanning in Troy.
</div>
I just pulled the sizes off the smallest image, and resized the others by proportion 730*752 > 594*612
its not a good idea to use html to resize images to suit the layout
actually resize the images with Irfanview, paintshop etc,
and serve them the correct size, (still with the sizes specified in the xhtml) smaller images = faster load times
notes
1:: the layout sucks, fixed width central column may look good on your pc,
mine is 2400px wide, what a waste of space
Ems and % are the dimensions of choice, width will adjust to screen and window size, keeping the same proportion as your design screen, on a wider range of systems
2:: incidental;
the only bugs in the code is the missing alt tags in those images