Securimage is an open-source free PHP CAPTCHA script for generating complex images and CAPTCHA codes to protect forms from spam and abuse.

Secureimage can be easily added into existing forms on your website to provide protection from spam bots. It can run on most any webserver as long as you have PHP installed, and GD support within PHP.

Securimage does everything from generating the CAPTCHA images to validating the typed code. Audible codes can be streamed to the browser with Flash for the vision impaired.

• Show an image in just 3 lines of code
• Validate submitted entries in less than 6 lines of code
• Customizable code length, character sets, and Unicode support
• TTF font support
• Easily add background images
• Several security features such as image distortion, random lines, and noise
• Flash button to stream audible codes in WAV format
• Ability to use a word list
• Case sensitive option for added security
• Display alphanumeric captchas, mathematical captchas, or a multi word captcha
• Highly customizable!