Yes I feel cropping by hand makes a difference. ANd it doesn't take that long.
Jim the problem is making thumbs with Arles means you have a thumb that is identical to the big picture. I have found that using closeups (when cropping the thumbs by hand) enables you to select what to show. For a big tit gallery you crop the tits more often. It is more of a turn on for the surfer. Some people say having the surfer click to see the big pictures turns him on more and gets him in the "clicking mood". More turned on means more apt to click to the tour to see more.
Here's 2 examples:
http://www.nshoneys.com/hosted1/hc/f....php?id=100031
http://www.nshoneys.com/hosted1/hc/g....php?id=100031
Not a big difference but the 30 minutes it takes me to crop by hand I like. And if using sponsor content the logo/watermark doesn't show when cropping by hand.
Licker4u, Photoshop is what most people use for making thumbs.