diff --git a/src/messenger/webim/client.php b/src/messenger/webim/client.php
index 8f3c4c2a..84d1aff0 100644
--- a/src/messenger/webim/client.php
+++ b/src/messenger/webim/client.php
@@ -24,6 +24,7 @@ require_once('libs/chat.php');
 require_once('libs/operator.php');
 require_once('libs/groups.php');
 require_once('libs/expand.php');
+require_once('libs/captcha.php');
 
 loadsettings();
 if($settings['enablessl'] == "1" && $settings['forcessl'] == "1") {
@@ -66,7 +67,7 @@ if( !isset($_GET['token']) || !isset($_GET['thread']) ) {
 			setup_logo();
 			$page['formname'] = topage(getgetparam('name'));
 			$page['formemail'] = topage($email);
-			$page['showcaptcha'] = $settings["enablecaptcha"] == "1" ? "1" : "";
+			$page['showcaptcha'] = $settings["enablecaptcha"] == "1" && can_show_captcha() ? "1" : "";
 			$page['info'] = topage($info);
 			expand("styles", getchatstyle(), "leavemessage.tpl");
 			exit;
diff --git a/src/messenger/webim/leavemessage.php b/src/messenger/webim/leavemessage.php
index 2e30501a..a2c70df1 100644
--- a/src/messenger/webim/leavemessage.php
+++ b/src/messenger/webim/leavemessage.php
@@ -22,6 +22,7 @@
 require_once('libs/common.php');
 require_once('libs/chat.php');
 require_once('libs/expand.php');
+require_once('libs/captcha.php');
 
 $errors = array();
 $page = array();
@@ -62,7 +63,7 @@ if( !$email ) {
 }
 
 loadsettings();
-if($settings["enablecaptcha"] == "1") {
+if($settings["enablecaptcha"] == "1" && can_show_captcha()) {
 	$captcha = getparam('captcha');
 	$original = $_SESSION['captcha'];
 	if(empty($original) || empty($captcha) || $captcha != $original) {
@@ -75,7 +76,7 @@ if( count($errors) > 0 ) {
 	$page['formname'] = topage($visitor_name);
 	$page['formemail'] = $email;
 	$page['formmessage'] = topage($message);
-	$page['showcaptcha'] = $settings["enablecaptcha"] == "1" ? "1" : "";
+	$page['showcaptcha'] = $settings["enablecaptcha"] == "1" && can_show_captcha() ? "1" : "";
 	$page['info'] = topage($info);
 	setup_logo();
 	expand("styles", getchatstyle(), "leavemessage.tpl");
diff --git a/src/messenger/webim/libs/captcha.php b/src/messenger/webim/libs/captcha.php
index f87494e0..d7be0399 100644
--- a/src/messenger/webim/libs/captcha.php
+++ b/src/messenger/webim/libs/captcha.php
@@ -15,6 +15,10 @@
 	Copyright 2006 WebCheatSheet.com
 */
 
+function can_show_captcha() {
+	return extension_loaded("gd");
+}
+
 function gen_captcha() {
 	$md5_hash = md5(rand(0,9999)); 
 	return substr($md5_hash, 15, 5);