Android : SkiImageDecoder Factory : returned null when trying to decode a byte array

I have written a rest webservice from which the image is fetched and then i converted it into a byte array. The image is retrieved and when i check the length of the byte array it says 15.

How can i decode this image and view it on my android app.

The code i used is as follows

protected void onPostExecute(ArrayList res) { // TODO Auto-generated method stub

        // System.out.println("Helloooooo" + res.get(0).getimg_storage());
         System.out.println("HEllooooooooooo" + res);

     for (int i = 0; i < res.size(); i++) {
             data.add(res.get(i).getimg_storage());
       }

    System.out.println("datoooo" + data);
         //data = res.get(0).getimg_storage();


    int size = data.size();

    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    DataOutputStream out = new DataOutputStream(baos);
    try{
    for (String element : data) {
        out.writeUTF(element);
    }
    }

    catch(Exception e)
    {
        System.out.println("elemant error");


    }

    byte[] bytes = baos.toByteArray();

        System.out.println("Aiyooooooowwwwwwwwwwww" + bytes);
        System.out.println("lennnn" + bytes.length);

         Bitmap bitmap = BitmapFactory.decodeByteArray(bytes , 0, bytes.length);
        }


}