yiisoft/yii2 · error · yii\base\InvalidConfigException

Defined library '{$imageLibrary}' is not supported

Error message

Defined library '{$imageLibrary}' is not supported

What it means

Error "Defined library '{$imageLibrary}' is not supported" thrown in yiisoft/yii2.

Source

Thrown at framework/captcha/CaptchaAction.php:266

     * Renders the CAPTCHA image.
     * @param string $code the verification code
     * @return string image contents
     * @throws InvalidConfigException if imageLibrary is not supported
     */
    protected function renderImage($code)
    {
        if (isset($this->imageLibrary)) {
            $imageLibrary = $this->imageLibrary;
        } else {
            $imageLibrary = Captcha::checkRequirements();
        }
        if ($imageLibrary === 'gd') {
            return $this->renderImageByGD($code);
        } elseif ($imageLibrary === 'imagick') {
            return $this->renderImageByImagick($code);
        }

        throw new InvalidConfigException("Defined library '{$imageLibrary}' is not supported");
    }

    /**
     * Renders the CAPTCHA image based on the code using GD library.
     * @param string $code the verification code
     * @return string image contents in PNG format.
     */
    protected function renderImageByGD($code)
    {
        $image = imagecreatetruecolor($this->width, $this->height);

        $backColor = imagecolorallocate(
            $image,
            (int) ($this->backColor % 0x1000000 / 0x10000),
            (int) ($this->backColor % 0x10000 / 0x100),
            $this->backColor % 0x100
        );
        imagefilledrectangle($image, 0, 0, $this->width - 1, $this->height - 1, $backColor);

View on GitHub (pinned to 66f00d18a2)

When it happens

Trigger: Thrown at framework/captcha/CaptchaAction.php:266 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of yiisoft/yii2@66f00d18a2 (2026-08-17). Data as JSON: /api/errors/2aa969301be022ff. Report an issue: GitHub.