Creating proper thumbnails in Photoshop was a mission and a half. I found a handy Imagemagick incantation for thumbnails. Here's the one I'll use to create 400×400 centered thumbnails for the photo gallery.

convert -size 400x400 sacha-20051201.jpg -thumbnail '400x400>' -bordercolor black -border 200 -gravity center -crop 400x400+0+0 +repage test.jpg