Hiya gnat, there's a few good scripts:
Autogal SQL
http://www.jmbsoft.com - I happen to use this script, but not in love with it...its a solid script for the price.
Vanilla TGP
http://www.vanillatgp.com/ - I'm going to be testing this script out soon, I'll let you know how it goes.
Comus -
http://www.comusthumbs.com/ - Haven't used it and as a submitter I'm not in love with the older versions of the script, but I know a few people that swear by this script.
Brownie -
http://www.germesia.com/scripts/brownie/index.html - If you've been a gallery submitter, you'll know this script.
There's a few others like agtgp, and a few that escape my memory at the moment. Vanilla offers a free version takes 2%, Autogal offers a free version, but it has some database limitation, comus also offers a free version, but I think it's like a 1 or 2% skim.