code: public void saveAsPNG(File file, int width, int height) throws IOException, TranscoderException {
      PNGTranscoder t = new PNGTranscoder();
      t.addTranscodingHint(PNGTranscoder.KEY_WIDTH, new Float(width));
      t.addTranscodingHint(PNGTranscoder.KEY_HEIGHT, new Float(height));
      transcode(file, t);
    }
docs: Transcode file to PNG.
  
  @param file Output filename
  @param width Width
  @param height Height
  @throws IOException On write errors
  @throws TranscoderException On input/parsing errors.