osCommerce / oscommerce2

                $this->headers['Content-Transfer-Encoding'] = $this->content_transfer_encoding;

                if (!empty($this->images)) {

                    foreach ($this->images as $image) {

                        $this->body_html = str_replace('src="' . $image['filename'] . '"', 'src="cid:' . $image['id'] . '"', $this->body_html);

                    }

                    unset($image);

                }

                $this->headers['MIME-Version'] = '1.0';

                $this->headers['Content-Type'] = 'multipart/mixed; boundary="' . $boundary . '"';

                foreach ($this->images as $image) {

                    $this->body_html = str_replace('src="' . $image['filename'] . '"', 'src="cid:' . $image['id'] . '"', $this->body_html);

                }

                unset($image);