I probably just don't know where to look, but I'd really like the usernames to not be case sensitive. JoeBob, JOEBOB and joebob should all be the same user. Is there a setting I can change to allow that behavior? The first additional admin user I created wasn't able to log in because he capitalized his name.

Sorry as with passwords the case matters. No way unless you wish to hack Zenphoto core files which is for obvious reasons not recommended. Educate your users instead!

Really? Other CMS's don't use case sensitive usernames, so why should Zenphoto?

Really? I suppose you want not to use case sensitive passwords as well? How about just numeric ones--maybe just the number 9. You probably should study up on strong security measures.

I guess you are really out of sorts if you have a Unix based server--then even your file system is case sensitive.

Indeed, at least on Wordpress the case does not matter for the user name but not the password! But that does not meant that we have to do it that way.