PHPmailer - obrázek jako base64 - maximální limit

$mail = new PHPMailer(true);

try {
    $mail->setFrom('xxx@domena.cz', 'xxx');
    foreach ($recipients as $name => $email) {
      $mail->addBCC($email, $name);
    }

    $mail->CharSet = 'UTF-8';
    $mail->isHTML(true);
    $mail->WordWrap = 50;

    preg_match_all('/img.*?>/', $values['content'], $matches);

    $id = 0;
    foreach ($matches[0] as $src) {
        $imgdata = explode(',',$src);
        $mime = explode(';', $imgdata[0]);
        $imgtype = explode(':', $mime[0]);

        $mail->AddStringEmbeddedImage(base64_decode($imgdata[1]), 'image'.$id, 'img_'.$id, $mime[1], $imgtype[1] );
        $values['content'] = str_replace($src, 'img alt="test" src="cid:image'.$id.'" style="border: none; />"', $values['content']);
        $id++;
    }

    $mail->Subject = $values['subject'];
    $mail->Body    = $values['content'];
    $mail->Send();

    $success = array(
        "info" => "Úspěch!",
        "description" => "Newsletter byl úspěšně odeslán"
    );
}
catch (phpmailerException $e) {
    $errors  = array(
        "info" => "Neúspěch!",
        "description" => $e->errorMessage()
    );
} catch (Exception $e) {
    $errors  = array(
        "info" => "Neúspěch!",
        "description" => $e->getMessage()
    );
}