I have had to make one.. 



I had to do this for one of my sites.  The only thing you will need to do is fix the paths in the code.

This is a simple captcha, But it should do it for most places. You can add picture or make your.. 
It has worked for my other site.. all the hard work it done..

How it works .... 

I made some php code that I put at the top of the form page.  (phpform.txt) 

The php code take one of the pictures and copies it to the image called picks.jpg so every time the picture is 
shown you see a different one.  Then in the form I add a field called picks that I test. 



Then make a thanks.htm and error page for wrong picks .. 

The processor.txt makes a formmail.cgi  


Thanks
Dr.D