Image generator for form submission

Need to generate image at random to prevent form submissions by scripts

[federico2005]

Hi,
I need a code to prevent spammers by submitting my forms through robot.

I know scripts can prevent that, by generating images at random bearing text to manually enter in a specific field - what you can see in the forms placed on any large site.

Anybody could suggest me a PHP code/script suitable for this need?
As I am not a 'PHP geek' I need something easy to manage and integrate with other form input checks.

Thanks

[jatar_k]

here is a good place to start, a lot of links at the bottom for a bunch of languages

[en.wikipedia.org...]

[dreamcatcher]

or check out the PHP Classes Repository, you are sure to find something there:

[phpclasses.org...]

dc

[federico2005]

Thanks for your suggestions, that could sounds a bit complicated for me, as involving libraries, classes etc...

So I have found a snippet of code, which does not require user to manually enter the text displayed on the image generated at random, but requires to perform a sum among two numbers generated at random.

It seems a code easy to handle. What could be the disvantages of such solution, respect to image one?

If you have a look to this script is,the Url is: [zend.com...]

[dreamcatcher]

btw, a little late now, but I found this tutorial at Sitepoint:

[sitepoint.com...]

dc