public static void main(String[] args) { if (args.length < 1) { System.out.printf("Usage: ImageProcessor205BW <input image>\n"); return; } String input_filename = args[0]; if (!input_filename.toLowerCase().endsWith(".png")) ErrorExit("Input file must be a PNG image.\n"); String output_filename = null; if (args.length > 1) output_filename = args[1]; else output_filename = input_filename.substring(0, input_filename.length() - 4) + "_output.png"; Color[][] inputPixels = load_image(input_filename); int[][] inputIntensities = ColoursToIntensities(inputPixels); int[][] resultIntensities = ProcessImage(inputIntensities); Color[][] resultPixels = IntensitiesToColours(resultIntensities); save_image(resultPixels, output_filename); }