U can connect to server through ftp from code and download it to your server or local and you can show it . 


    function example_download_image() {
          $local_file = 'tmp/download.jpg';
          $server_file = 'tmp_server/download.jpg';
          $ftp_server = "ftp.server.com";
          $conn_id = ftp_connect($ftp_server);
          $ftp_user_name = "user_name";
          $ftp_user_pass = "password";
          $login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass);
          ftp_pasv($conn_id, true);
          if (ftp_get($conn_id, $local_file, $server_file, FTP_BINARY)) {
          }
          else {
            drupal_set_message("There was a problem\n");
          }
          ftp_close($conn_id);
        }