HTML emails help bit urgent .

okay i dont know where to put this topic, if it needs to be moved then please do so, I have been creating a mass mailer with this class, 

<?php
class SimpleMail
{
    private $toAddress;
    private $CCAddress;
    private $BCCAddress;
    private $fromAddress;
    private $subject;
    private $sendText;
    private $textBody;
    private $sendHTML;
    private $HTMLBody;

    public function __construct() {
        $this->toAddress = '';
        $this->CCAddress = '';
        $this->BCCAddress = '';
        $this->fromAddress = '';
        $this->subject = '';
        $this->sendText = false;
        $this->textBody = '';
        $this->sendHTML = true;
        $this->HTMLBody = '';
    }

    public function setToAddress($value) {
        $this->toAddress = $value;
    }

    public function setCCAddress($value) {
        $this->CCAddress = $value;
    }

    public function setBCCAddress($value) {
        $this->BCCAddress = $value;
    }

    public function setFromAddress($value) {
        $this->fromAddress = $value;
    }

    public function setSubject($value) {
        $this->subject = $value;
    }

    public function setSendText($value) {
        $this->sendText = $value;
    }

    public function setTextBody($value) {
        $this->sendText = false;
        $this->textBody = $value;
    }

    public function setSendHTML($value) {
        $this->sendHTML = $value;
    }

    public function setHTMLBody($value) {
        $this->sendHTML = true;
        $this->HTMLBody = $value;
    }

    public function send($to = null, $subject = null, $message = null,
        $headers = null) {

        $success = false;
        if (!is_null($to) && !is_null($subject) && !is_null($message)) {
            $success = mail($to, $subject, $message, $headers);
            return $success;
        } else {
            $headers = array();
            if (!empty($this->fromAddress)) {
                $headers[] = 'From: ' . $this->fromAddress;
            }

            if (!empty($this->CCAddress)) {
                $headers[] = 'CC: ' . $this->CCAddress;
            }

            if (!empty($this->BCCAddress)) {
                $headers[] = 'BCC: ' . $this->BCCAddress;
            }

            if ($this->sendText && !$this->sendHTML) {
                $message = $this->textBody;
            } elseif (!$this->sendText && $this->sendHTML) {
                $headers[] = 'MIME-Version: 1.0';
                $headers[] = 'Content-type: text/html; charset="iso-8859-1"';
                $headers[] = 'Content-Transfer-Encoding: 7bit';
              //  $headers[] .= 'Content-Transfer-Encoding: quoted-printable';
                $message = $this->HTMLBody;
            } elseif ($this->sendText && $this->sendHTML) {
                $boundary = '==MP_Bound_xyccr948x==';
                $headers[] = 'MIME-Version: 1.0';
                $headers[] = 'Content-type: multipart/alternative; boundary="' .
                    $boundary . '"';

                $message = 'This is a Multipart Message in MIME format.' . "\n";
                $message .= '--' . $boundary . "\n";
                $message .= 'Content-type: text/plain; charset="iso-8859-1"' . "\n";
                $message .= 'Content-Transfer-Encoding: 7bit' . "\n\n";
               // $message .= 'Content-Transfer-Encoding: quoted-printable' . "\n\n";
                $message .= $this->textBody  . "\n";
                $message .= '--' . $boundary . "\n";

                $message .= 'Content-type: text/html; charset="iso-8859-1"' . "\n";
                $message .= 'Content-Transfer-Encoding: 7bit' . "\n\n";
                $message .= $this->HTMLBody  . "\n";
                $message .= '--' . $boundary . '--';
            }

            $success = mail($this->toAddress, $this->subject, $message,
                join("\r\n", $headers));
            return $success;
        }
    }
}
?>

now the problem is when ever gmail recives the image code , 

<img src="http://yourdomain.com/image.jpg" >

it escapes them like this :

<img src=\"http://yourdomain.com/image.jpg\" >

and the image is not read how could i resolve this ???