Display multiple images using ImageIO and ByteArrayOutputStream

Question

I'm trying to display multiple images from a directory using ImageIO and ByteArrayOutputStream.

For one image I can do this easily:

public byte[] getImage() {
    try {
        InputStream inputStream = new FileInputStream("image.jpg");

        BufferedImage bufferedImage = ImageIO.read(inputStream);
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ImageIO.write(bufferedImage, "jpg", byteArrayOutputStream);

        return byteArrayOutputStream.toByteArray();
    } catch (IOException e) {
        System.out.println(e.getMessage());
    }
    return null;
}

What is the best approach to display multiple images?

I'm doing the following:

1. Create a new Buffered Image with size appropriate to fit the images.
2. Get the graphics object from the new Buffered Image
3. Draw the images via the graphics object

Here is the code I'm using:

    public byte[] retrieveFaceDb() {

        // TODO:

        String faceDbPath = Utils.commandLineArgs[2];

        File dir = new File(faceDbPath);

        if (dir.isDirectory()) {

            ByteArrayOutputStream finalByteArrayOutputStream = new ByteArrayOutputStream();

            BufferedImage[] buffImages = new BufferedImage[10];

            int type = 0;
            int idx = 0;
            for (final File f : dir.listFiles()) {

                try {
                    buffImages[idx] = ImageIO.read(f);
                    type = buffImages[idx].getType();

                    idx ++;

                } catch (final IOException e) {
                    // handle errors here
                }
            }

            int num = 0;
            BufferedImage finalBufferedImage = new BufferedImage(buffImages[0].getWidth()*10, buffImages[0].getHeight(), type);
            for (int i = 0; i < 1; i++) {
                for (int j = 0; j < 10; j++) {
                    finalBufferedImage.createGraphics().drawImage(buffImages[num], buffImages[0].getWidth()*j, buffImages[0].getHeight()*i, null);
                    num ++;
                }
            }

            try {
                ImageIO.write(finalBufferedImage, "png", finalByteArrayOutputStream);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            return finalByteArrayOutputStream.toByteArray();

//          try {
//              return java.nio.file.Files.readAllBytes(dir.toPath());
//          } catch (IOException e) {
//              // TODO Auto-generated catch block
//              e.printStackTrace();
//          }
        }

        return null;
    }

Is there a better way to do this? Thank you.