FlexCaptcha is the worlds most advanced freeware Captcha asp.net control. Most significantly FlexCaptcha support writing captcha images to either disk or directly to http stream bypassing disk writing all toghether. In addition the captcha can reload and have many custom settings. FlexCaptcha default works out of the box and can be embedded in other server controls. For advanced users, the fast direct http writing can be utilized. FlexCaptcha comes with full documentation and many examples.