I need to develop a form for a customer that has an image identifier to type in. He says he gets too much spam on his current form. How do you do this?

You need to provide better description than the general reguest you submited in first place. Elaborate on requirements...

He means those things where you have to type in the letters visible in an image to validate the submission.

This requires a server-side script.

commented: You correct, somehow I overlooked the problem :) +8