I prefer the look of square thumbs (nice and neat) but am having trouble with heads being chopped off on some portrait images. Is there any way to control what portion of the image is used to make the thumb? I was looking into adding a "regenerate thumb" feature using this javascript, but I think I'm too stupid to figure it out. ;)
I ended up using this very snazzy script. I just added an update_thumbnails.php file and link to it from the edit photo page. If anyone wants to see it, I can send it your way. I don't know how useful it will be as I've ended up re-writing my image gallery from the ground up.