private String buildCommand(String[] files, String output) {
		String result = "./gifsicle";
		result += " --delay=" + delay;
		if (loop)
			result += " --loop";
		for (String f : files) {
			result += " " + f;
		}
		result += " > " + output;
		System.out.println("executing: \n" + result);
		return result;
	}