I believe that snes9x is a super nintendo emulator and for super nintendo the screenshot archive has a modifed zSnes.
Doh! You are right, I wasn't thinking too hard.

Yes, for SNES, you're best bet is to use Zsnesw which is located at my site. Thanks for that TalkingOctopus, and thanks for the VirtuaNES tip - I think I'll modify it and perhaps add it to the site with the others. Or at least add the modifed line there for future reference.