Some nice designs there and a very good site
, I’m not a particular fan of opening the larger preview images in a new browser/tab (portfolio) though. Try a script such as prettyphoto
which adds a very nice effect to showing larger preview images.
It’s really simple to use also and fairly self explanatory script with the site help, and importantly freeware
and you could use noscript tags for those without java redirecting to a page with the image, not just the image.