private void findDNGFiles(AbstractQueue<String> queue, String path) {
		System.out.print(".");
		File root = new File(path);
        File[] list = root.listFiles();

        if (list == null) return;

        for (File f : list) {
            if (f.isDirectory()) {
            	findDNGFiles(queue, f.getAbsolutePath());
            }
            else {
            	if (f.getAbsolutePath().toString().toLowerCase().endsWith("dng")) {
            		queue.add(f.getAbsolutePath().toString());
            	}
            }
        }
	}