bit = BitmapFactory.decodeFile(Environment
        .getExternalStorageDirectory().getAbsolutePath()
        + "/DCIM/Camera/test.jpg");

    Log.i("wechat", "压缩前图片的大小" + (bit.getByteCount() / 1024 / 1024)
        + "M宽度为" + bit.getWidth() + "高度为" + bit.getHeight());

      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      int quality = Integer.valueOf(editText.getText().toString());
      bit.compress(CompressFormat.JPEG, quality, baos);
      byte[] bytes = baos.toByteArray();
      bm = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
      Log.i("wechat", "压缩后图片的大小" + (bm.getByteCount() / 1024 / 1024)
          + "M宽度为" + bm.getWidth() + "高度为" + bm.getHeight()
          + "bytes.length= " + (bytes.length / 1024) + "KB"
          + "quality=" + quality);

BitmapFactory.Options options = new BitmapFactory.Options();
      options.inSampleSize = 2;

      bm = BitmapFactory.decodeFile(Environment
          .getExternalStorageDirectory().getAbsolutePath()
          + "/DCIM/Camera/test.jpg", options);
      Log.i("wechat", "压缩后图片的大小" + (bm.getByteCount() / 1024 / 1024)
          + "M宽度为" + bm.getWidth() + "高度为" + bm.getHeight());

Matrix matrix = new Matrix();
      matrix.setScale(0.5f, 0.5f);
      bm = Bitmap.createBitmap(bit, 0, 0, bit.getWidth(),
          bit.getHeight(), matrix, true);
      Log.i("wechat", "压缩后图片的大小" + (bm.getByteCount() / 1024 / 1024)
          + "M宽度为" + bm.getWidth() + "高度为" + bm.getHeight());

BitmapFactory.Options options2 = new BitmapFactory.Options();
      options2.inPreferredConfig = Bitmap.Config.RGB_565;

      bm = BitmapFactory.decodeFile(Environment
          .getExternalStorageDirectory().getAbsolutePath()
          + "/DCIM/Camera/test.jpg", options2);
      Log.i("wechat", "压缩后图片的大小" + (bm.getByteCount() / 1024 / 1024)
          + "M宽度为" + bm.getWidth() + "高度为" + bm.getHeight());

bm = Bitmap.createScaledBitmap(bit, 150, 150, true);
      Log.i("wechat", "压缩后图片的大小" + (bm.getByteCount() / 1024) + "KB宽度为"
          + bm.getWidth() + "高度为" + bm.getHeight());

 File file = new File(Environment.getExternalStorageDirectory()
     .getAbsolutePath() + "/DCIM/Camera/test.jpg");
     Log.i("wechat", "file.length()=" + file.length() / 1024);

FileInputStream fis = null;
    try {
      fis = new FileInputStream(file);
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    }
    try {
      Log.i("wechat", "fis.available()=" + fis.available() / 1024);
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }