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 and submit spam where they can. It is well known that programmers
can do programs for many jobs, including visiting a large amount of
sites on the Internet by following links from page to page and collect
emails listed on websites, submit contact forms, or even trying to
break passwords 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 a form.
