Problem with getting resized image's bytes

Question

I've got a problem with getting correct bytes of a newly resized image. The flow is that I retrive an image from the filesystem. Due to the fact that it is large I resize it to a 50x50px thumbnail. I can display this thumbnail in #benchmark1 (see code below). Unfortunately something's wrong with my imageToBytes funtion which returns reasonably small size of image but is totally useless - I can't make an image of it anymore so at #benchmark2 the application either crashes or keeps freezing. I saved this byte array on my disk and tried to preview under Windows how does it look but I got a message "Preview unavailabe". I did some digging in the Internet and I supposed that it's because I don't use any jpg or png encoders to save the file. Actually I think that it's not the case, as the bytes returned from method imageToBytes look weird - I cannot even make a new image of them and display it without any saving in memory.
                              byte[] bytes = FileHandler.readFile (
                                      FileHandler.PHOTOS_PATH, fileName);
                              Image img2 = Image.createImage (bytes, 0, bytes.length);
                              img2 = ImageHandler.getInstance ().resize (img2);
                                                //#benchmark1
                              bytes = ImageUtils.imageToBytes (img2);
                              img2 = Image.createImage (bytes, 0, bytes.length);
                                                //#benchmark2my imageToBytes function is as follows:
     public static byte[] imageToBytes (Image img)
          int[] imgRgbData = new int[img.getWidth () * img.getHeight ()];
          byte[] imageData = null;
          try
               img.getRGB (imgRgbData, 0, img.getWidth (), 0, 0, img.getWidth (),
                       img.getHeight ());
          catch (Exception e)
          ByteArrayOutputStream baos = new ByteArrayOutputStream ();
          DataOutputStream dos = new DataOutputStream (baos);
          try
               for (int i = 0; i < imgRgbData.length; i++)
                    dos.writeInt (imgRgbData);
               imageData = baos.toByteArray ();
               baos.close ();
               dos.close ();
          catch (Exception e)
          return imageData;
I've run totally out of any idea what's wrong, please help!
Edited by: crawlie on Jul 17, 2010 6:21 PM                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Answer 1

Hey Crawlie,
Please note that simply writing int values into ByteArrayOutputStream will not suffice. Please have a look at the following conversion from int pixel value into byte[4]:
public static final byte[] intToByteArray(int value) {
        return new byte[] {
                (byte)(value >>> 24),
                (byte)(value >>> 16),
                (byte)(value >>> 8),
                (byte)value
}Good Luck!
Daniel