Помогите прикрутить капча, пожалуйста!

Форма:
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<?php
error_reporting(0);
function show_form()
{
?>

<form action="" method=post>
<div>
<p>
<input name="input_name[0]" type="text" class="contact-form" value="<?=substr(htmlspecialchars(trim($_POST['input_name'][0])), 0, 500);?>" size="39" >
<input type="hidden" name="check[]2" value="1">
<b>Name*</b></p>
<p>
<input name="input_name[1]" type="text" class="contact-form" value="<?=substr(htmlspecialchars(trim($_POST['input_name'][1])), 0, 500);?>" size="39" >
<input type="hidden" name="check[]3" value="1">
<b>Email*</b></p>
<p>
<input name="input_name[2]" type="text" class="contact-form" value="<?=substr(htmlspecialchars(trim($_POST['input_name'][2])), 0, 500);?>" size="39" >
<input type="hidden" name="check[]4" value="1">
<b>Phone*</b></p>
<p>
<select name="input_name[3]" class="search-select2">
<option value="Bangkok"<?if(htmlspecialchars($_POST['input_name'][3]) == "Bangkok") echo ' SELECTED';?>>Bangkok
<option value="Pattaya"<?if(htmlspecialchars($_POST['input_name'][3]) == "Pattaya") echo ' SELECTED';?>>Pattaya
<option value="Phuket"<?if(htmlspecialchars($_POST['input_name'][3]) == "Phuket") echo ' SELECTED';?>>Phuket
<option value="Samui"<?if(htmlspecialchars($_POST['input_name'][3]) == "Samui") echo ' SELECTED';?>>Samui
<option value="Chiang Mai"<?if(htmlspecialchars($_POST['input_name'][3]) == "Chiang Mai") echo ' SELECTED';?>>Chiang Mai
<option value="Khon Kaen"<?if(htmlspecialchars($_POST['input_name'][3]) == "Khon Kaen") echo ' SELECTED';?>>Khon Kaen
<option value="Hat Yai"<?if(htmlspecialchars($_POST['input_name'][3]) == "Hat Yai") echo ' SELECTED';?>>Hat Yai
<option value="Hua Hin"<?if(htmlspecialchars($_POST['input_name'][3]) == "Hua Hin") echo ' SELECTED';?>>Hua Hin
<option value="Other"<?if(htmlspecialchars($_POST['input_name'][3]) == "Other") echo ' SELECTED';?>>Other
</select>
<input type="hidden" name="check[]5" value="1">
<b>Region*</b></p>
<p>
<select name="input_name[4]" class="search-select2">
<option value="House"<?if(htmlspecialchars($_POST['input_name'][4]) == "House") echo ' SELECTED';?>>House
<option value="Condo/Apartment"<?if(htmlspecialchars($_POST['input_name'][4]) == "Condo/Apartment") echo ' SELECTED';?>>Condo/Apartment
<option value="Villa"<?if(htmlspecialchars($_POST['input_name'][4]) == "Villa") echo ' SELECTED';?>>Villa
<option value="Land"<?if(htmlspecialchars($_POST['input_name'][4]) == "Land") echo ' SELECTED';?>>Land
<option value="Multi dwelling projects"<?if(htmlspecialchars($_POST['input_name'][4]) == "Multi dwelling projects") echo ' SELECTED';?>>Multi dwelling projects
<option value="Business"<?if(htmlspecialchars($_POST['input_name'][4]) == "Business") echo ' SELECTED';?>>Business
<option value="Office"<?if(htmlspecialchars($_POST['input_name'][4]) == "Office") echo ' SELECTED';?>>Office
<option value="Shop House"<?if(htmlspecialchars($_POST['input_name'][4]) == "Shop House") echo ' SELECTED';?>>Shop House
</select>
<input type="hidden" name="check[]6" value="1">
<b>Property*</b></p>
<p>
<select name="input_name[5]2" class="search-select2">
<option value="Rent">Rent
<option value="Buy">Buy
</select>
<strong>Buy/Rent</strong></p>
<p>
<select name="input_name[6]" class="search-select2">
<option value="Any" selected>Any</option>
<option value="5,000-55,000">5,000-55,000</option>
<option value="55,000-130,000">55,000-130,000</option>
<option value="130,000-250,000">130,000-250,000</option>
<option value="250,000-500,000">250,000-500,000</option>
<option value="500,000-1,000,000">500,000-1,000,000</option>
<option value="1,000,000 -3,000,000">1,000,000 -3,000,000</option>
<option value="3,000,000 -7,000,000">3,000,000 -7,000,000</option>
<option value="7,000,000 -15,000,000">7,000,000 -15,000,000</option>
<option value="15,000,000 -...">15,000,000 -...</option>
</select>
</span>
<input type="hidden" name="check[]7" value="2">
<b>Budget range, THB</b></p>
<p>
<textarea name="input_name[7]" cols="30" rows="10" class="contact-mess"><?=substr(htmlspecialchars(trim($_POST['input_name'][6])), 0, 10000);?>
</textarea>
<input type="hidden" name="check[]" value="1">
<b>Request*</b></p>
<p>Captcha:
<input type="text" id="code" name="code" size="4" maxlength="4">
<img align="absmiddle" src="captcha/captcha.php"> </p>
<p>
<input name="submit" type="submit" class="btn" id="submit" value="Send">
</p>
</div>
</form><div align="center">* Please fill in all required fields</div>
<?
}
function complete_mail() {
if (empty($_POST['code']) or empty($_SESSION['code'])) {
echo '<br><b>Add captcha please!</b>';
$sendemail = 'No';
} elseif ($_POST['code'] != $_SESSION['code']) {
echo '<br><b>Captcha is wrong!</b>';
$sendemail = 'No';
}

$empty_input[] = 'Name';
$empty_input[] = 'Email';
$empty_input[] = 'Phone';
$empty_input[] = 'Region';
$empty_input[] = 'Property';
$empty_input[] = 'Rent/Buy';
$empty_input[] = 'Budget, max., THB';
$empty_input[] = 'Request';
for ($i=0; $i<count($_POST['input_name']); $i++) {
$_POST['input_name'][$i] = substr(htmlspecialchars(trim($_POST['input_name'][$i])), 0, 100000);
if(substr(htmlspecialchars(trim($_POST['check'][$i])), 0, 1) == 1) {
if(empty($_POST['input_name'][$i])) {
$sendemail = 'No';
echo '<br /><b>Fill please '.$empty_input[$i].'!</b>';

}
}
}
if($sendemail == 'No') show_form();
$mess = '';
$mess .= '<b>Name: </b>'.$_POST['input_name'][0].'<br />';
$mess .= '<b>Email: </b>'.$_POST['input_name'][1].'<br />';
$mess .= '<b>Phone: </b>'.$_POST['input_name'][2].'<br />';
$mess .= '<b>Region: </b>'.$_POST['input_name'][3].'<br />';
$mess .= '<b>Property: </b>'.$_POST['input_name'][4].'<br />';
$mess .= '<b>Rent/Buy: </b>'.$_POST['input_name'][5].'<br />';
$mess .= '<b>Budget, max., THB: </b>'.$_POST['input_name'][6].'<br />';
$mess .= '<b>Request: </b>'.$_POST['input_name'][7].'<br />';

require 'manager/includes/controls/class.phpmailer.php';

$mail = new PHPMailer();
$mail->From = 'Email'; // от кого email
$mail->FromName = 'Name'; // от кого имя
$mail->AddAddress('inf@1800-realty.com,sandalvl@mail.ru', 'inf@1800-realty.com,sandalvl@mail.ru'); // кому - адрес, Имя
$mail->IsHTML(true); // выставляем формат письма HTML
$mail->Subject = 'Looking For from thai-property.co'; // тема письма
$mail->Body = $mess;



if($sendemail != 'No'){
// отправляем наше письмо
if (!$mail->Send()) die ('Mailer Error: '.$mail->ErrorInfo);
echo '<h1>Thank you!</h1><p>Thank you for listing with us and we hope you will find your perfect property quickly.<br />Admin will check request and it will be appear online one working day.</p>';
}
}
if (!empty($_POST['submit'])) complete_mail();
else show_form();
?>
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Капча:
------------
<?php session_start();

$width = 100; //Ширина изображения
$height = 55; //Высота изображения
$font_size = 15; //Размер шрифта
$let_amount = 4; //Количество символов, которые нужно набрать
$fon_let_amount = 30; //Количество символов, которые находятся на фоне
$path_fonts = 'fonts/'; //Путь к шрифтам


$letters = array('2','3','4','5','6','7','9');
$colors = array('10','30','50','70','90','110','130','150','170','190','210');

$src = imagecreatetruecolor($width,$height);
$fon = imagecolorallocate($src,255,255,255);
imagefill($src,0,0,$fon);

$fonts = array();
$dir=opendir($path_fonts);
while($fontName = readdir($dir))
{
if($fontName != "." && $fontName != "..")
{
$fonts[] = $fontName;
}
}
closedir($dir);

for($i=0;$i<$fon_let_amount;$i++)
{
$color = imagecolorallocatealpha($src,rand(0,255),rand(0,255),rand(0,255),100);
$font = $path_fonts.$fonts[rand(0,sizeof($fonts)-1)];
$letter = $letters[rand(0,sizeof($letters)-1)];
$size = rand($font_size-2,$font_size+2);
imagettftext($src,$size,rand(0,45),rand($width*0.1,$width-$width*0.1),rand($height*0.2,$height),$color,$font,$letter);
}

for($i=0;$i<$let_amount;$i++)
{
$color = imagecolorallocatealpha($src,$colors[rand(0,sizeof($colors)-1)],$colors[rand(0,sizeof($colors)-1)],$colors[rand(0,sizeof($colors)-1)],rand(20,40));
$font = $path_fonts.$fonts[rand(0,sizeof($fonts)-1)];
$letter = $letters[rand(0,sizeof($letters)-1)];
$size = rand($font_size*2.1-2,$font_size*2.1+2);
$x = ($i+1)*$font_size + rand(4,7);
$y = (($height*2)/3) + rand(0,5);
$cod[] = $letter;
imagettftext($src,$size,rand(0,15),$x,$y,$color,$font,$letter);
}

$_SESSION['code'] = implode('',$cod);

header ("Content-type: image/gif");
imagegif($src);
?>
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Спасибо!