private void loadImagesFile(String fnm)
  /* Formats:
        o <fnm>                     // a single image
        n <fnm*.ext> <number>       // a numbered sequence of images
        s <fnm> <number>            // an images strip
        g <name> <fnm> [ <fnm> ]*   // a group of images 

     and blank lines and comment lines.
  */
  { 
    String imsFNm = IMAGE_DIR + fnm;
    System.out.println("Reading file: " + imsFNm);
    try {
      InputStream in = this.getClass().getResourceAsStream(imsFNm);
      BufferedReader br = new BufferedReader( new InputStreamReader(in));
      // BufferedReader br = new BufferedReader( new FileReader(imsFNm));
      String line;
      char ch;
      while((line = br.readLine()) != null) {
        if (line.length() == 0)  // blank line
          continue;
        if (line.startsWith("//"))   // comment
          continue;
        ch = Character.toLowerCase( line.charAt(0) );
        if (ch == 'o')  // a single image
          getFileNameImage(line);
        else if (ch == 'n')  // a numbered sequence of images
          getNumberedImages(line);
        else if (ch == 's')  // an images strip
          getStripImages(line);
        else if (ch == 'g')  // a group of images
          getGroupImages(line);
        else
          System.out.println("Do not recognize line: " + line);
      }
      br.close();
    } 
    catch (IOException e) 
    { 
    	System.out.println("Error reading file: " + imsFNm);
    }
  }  // end of loadImagesFile()