Hi Deb,
I see your making progress in working-out the 3:2 issues.
Auctiva's thumbnail viewer has it's main image loading by stored 400 x 300 (landscape) pics and the thumbs are stored 80 x 80, so there's really no easy method to upscale their viewer, other than code changes and alternate picture links.
The link to listing code you gave is a very good example of a 3:2 viewer and thumbs. Those pics all appear to be exactly 3:2 at 430 x 645 and the thumbs are displayed at 70 x 105 by using the same picture, but forcing the image to thumb size using height and width in the code. Note the use of the darker grey on the background of the cells, so the pics have a very small mat surround.
You could certainly try to substitue your description and measurements elements to the right and replace theirs. They have six thumbs. You could also add another vertical row of thumbs for 12.
This seller is doing exactly what I suggested with either a pro cam or cropping software. To me, the 3:2 is perfect for modeling shots, and this is a perfect example of use.
Your old thumbviewer is actually very close to exactly what this example does. They are even using almost identical Java code for preLoad and imageChange.
Danno