This question has been answered by BobRay. See the first response.
[[!QuipReply? &closeAfter=`0` &thread=`Guestbook` &tplAddComment=`guestbookAddComment` &tplPreview=`guestbookPreview` &dateFormat=`%Y-%m-%d %H:%M` &autoConvertLinks=`0` &recaptcha=`1` &disableRecaptchaWhenLoggedIn=`0`]]
<img src="[[++assets_path]]components/captcha/captcha.php" alt="Captcha Image" />
<img src="./assets/components/captcha/captcha.php" alt="Captcha Image" />
<img src="./assets/components/captcha/captcha.php" alt="Captcha Image" /> <input id="my_textcha" type="text" /> <div id="mytst">[[!samtcha]]</div>
<?php echo $_SESSION['veriword'];