Why do I have to click a picture to submit this form?

These forms get a good deal of spam. To make sure that you are a human and not a computer sending spam, we ask that you do something that is easy for a human to do but hard for a computer. To a computer, an image is just a set of numbers while to a human an image represents something in the physical world that can easily be recognised. As we humans are very visual, image recognition is fast and accurate. Programs exist to do the same for computers but they are complex, slow and prone to error. Thankfully for us right now they are fairly rare as well.

Why would a spammer post spam to this web form?
Because the contents of forms sometimes end up on this website (such as in the case of comments) and they can contain links to other websites. "So?" you say? Well, a link from this website, which has a fairly high Page Rank in Google, translates into a vote of confidence for that spammer's website. Google will notice that and elevate the spammer's website in Google results. And we don't want that, now do we? Aside from that, its annoying and ugly to have spam garbage all over this website. So that's why we ask you to do something simple to prove that you are a human and not a spammer computer.

Can I get this for my website?
Yes. Check out JustHumans.com. Accounts are free to set up and thousands of people are using it.