A user can request his password be reset during the login process. An email is sent with a link to the password page that will let him change the password.
There is no script that will actually send a password. Zenphoto does not actually know the password. It is never stored in clear text.
A Script could be built to create a new password and send it to a user. You would have to make use of the saveAdmin() function in functions-auth.php to update the user with a new password. See the documentation on that function for details. You can use the usf8 class function send_mail() to do the e-mail. Of course, e-mailing a passwrod is not the most secure thing to do.