Webbo, Zenfor wants "non-forum related" advice. CAPTCHA routines made to integrate into Snitz aren't the ideal solution.
That said, there are pros and cons for using CAPTCHA at all. Some advise NEVER to use them; but spam-bots will bury you if you don't. I cannot recommend any particular anti-spam routine from the information provided.
You could do something like this, you would have to edit the database path and put images titled "a"-"z" and "0"-"9" into an images folder. The database would require a table titled "CAPTCHA" with two fields (DTG) and (Captured), both of which set to varchar(16).
This method would write the CAPTCHA into the database set to the exact second of its creation (to preclude duplicates). When the user submits the form for validation, the CAPTCHA is deleted from the table.
"inc_captcha.asp"