Convert a 2D array of int ranging from 0-256 into a grayscale png?

Question

How can I convert a 2D array of ints into a grayscale png. right now I have this:

    BufferedImage theImage = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
    for(int y = 0; y<100; y++){
        for(int x = 0; x<100; x++){
            theImage.setRGB(x, y, image[y][x]);
        }
    }
    File outputfile = new File("saved.bmp");
    ImageIO.write(theImage, "png", outputfile);

but the image comes out blue. how can I make it a grayscale.

image[][] contains ints ranging from 0-256.