我可以从Silverlight中的BitmapImage获取byte []吗？

using System;
using System.IO;
using System.Windows.Media.Imaging;

public byte[] ConvertBitmapImageToByteArray(BitmapImage bitmapImage)
{
    WriteableBitmap writeableBitmap = new WriteableBitmap(bitmapImage);
    MemoryStream memoryStream = new MemoryStream();
    writeableBitmap.SaveJpeg(memoryStream, writeableBitmap.PixelWidth, writeableBitmap.PixelHeight, 0, 100);
    return memoryStream.ToArray();
}