Securimage-WP adds powerful CAPTCHA protection to comment forms on posts and pages to help prevent comment spam from getting onto your site. CAPTCHA
If you install Securimage-WP, there is a test script that will tell you whether or not your system meets the requirements.
From the Securimage-WP settings menu, enable the
Debug Image Errors option, save the settings, and then click the link labeled
View Image Directly. Ideally, this will reveal any error messages that may be causing the image generation to fail. Try to troubleshoot the error, or contact us for assistance.
CAPTCHA codes have expiration times in order to reduce the amount of time spammers have to break the CAPTCHA. The default time is 15 minutes. After this time lapses, the CAPTCHA refreshes since it is no longer valid. You can customize this setting in the options menu.