What is Image Verification ( Captcha )?

A security test to determine whether or not the user is human. This will ensure that only human visitors will actually submit the form and not spamming bots that are browsing the web from site to site. Clever programmers can create scripts to visit large numbers of sites, follow links from page to page and harvest email addresses listed on pages or contact forms. They can also attempt to crack password protected sites by trying to login over and over again with computer generated passwords.

Fortunately, it is impossible for a non-human ( ex. computer program ) to extract a word or a combination of letters and numbers from an image, if the letters and numbers are not all of the same size and of similar font. This is why the Image Verification security method ensures that only people actually can submit this form.