Forms

[InNeedofHelp]

Hey DD, I have what may be a dumb question, but I'm curious. I'm planning to start a website with my freinds over the summer, one that involves a registration page. And when I'm on the web and registering for things such as forums, I always find these little pictures at the bottom of the registration form that have just like 4 letters, and I'm asked to write what i see into a little box. For example i might see a picture and have to enter into one of the input boxes WKX4.

So my question is:
What is that thing for, is there any security purpose for it or something?
and also, how would someone go about generating one of those to use in their own custom registration forms?

Thanks in advance

[Twey]

The point is to stop bots from registering. It is relatively difficult to write a bot that can decipher text from within an image.

You probably want to have a look at server-side image generation. Since you're using PHP, GD will most likely be your first option.