[thelist] Image Challenge System

[Russ]

Hello,

I'm curious to know if anyone has utilized an Image Challenge System in
order to prevent SPAM from appearing in comments sections on websites.

Just so I'm clear:  An image appears with some sort of warped/squiggly
letters and numbers combinations and challenges the user to match that
in a text field.  Success or failure dictates what happens next,
obviously.

Has anyone seen a 3rd part solution or a share/freeware solution out
there and/or used one that they'd recommend?

Thanks,

Russ