Convert uri to Bitmap

UriToBitmap.java

    public Bitmap getThumbnail(Uri uri) throws FileNotFoundException, IOException {
        InputStream input = this.getContentResolver().openInputStream(uri);

        BitmapFactory.Options onlyBoundsOptions = new BitmapFactory.Options();
        onlyBoundsOptions.inJustDecodeBounds = true;
        onlyBoundsOptions.inDither=true;//optional
        onlyBoundsOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//optional
        BitmapFactory.decodeStream(input, null, onlyBoundsOptions);
        input.close();
        if ((onlyBoundsOptions.outWidth == -1) || (onlyBoundsOptions.outHeight == -1))
            return null;

        int originalSize = (onlyBoundsOptions.outHeight > onlyBoundsOptions.outWidth) ? onlyBoundsOptions.outHeight : onlyBoundsOptions.outWidth;

        double ratio = (originalSize > THUMBNAIL_SIZE) ? (originalSize / THUMBNAIL_SIZE) : 1.0;

        BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
        bitmapOptions.inSampleSize = getPowerOfTwoForSampleRatio(ratio);
        bitmapOptions.inDither=true;//optional
        bitmapOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//optional
        input = this.getContentResolver().openInputStream(uri);
        Bitmap bitmap = BitmapFactory.decodeStream(input, null, bitmapOptions);
        input.close();
        return bitmap;
    }

    private static int getPowerOfTwoForSampleRatio(double ratio){
        int k = Integer.highestOneBit((int)Math.floor(ratio));
        if(k==0) return 1;
        else return k;
    }

How much is the value of THUMBNAIL_SIZE?

Please, what is the value of THUMBNAIL_SIZE ??