You could create a utility/captcha.phtml in your views/scripts folder, then in your catchaAction() set $this->view->captcha = $captcha->getCAPTCHAAsPng() instead of just echoing it in the action.

Then in the captcha.phtml just echo $this->captcha.

You may also need to set the view to be of type PNG. I've never done this so I'm not sure where to start.

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