Silverlight - 将BitmapImage转化为Stream或byte数组

先将BitmapImage转化为WriteableBitmap，然后得到base64字符串，然后可以得到base64的byte[]数组，再然后您可以把byte[]变成Stream

关键代码：

WriteableBitmap wb = new WriteableBitmap(img.Source as BitmapSource);//将Image对象转换为WriteableBitmap
byte[] b = Convert.FromBase64String(GetBase64Image(wb));//得到byte数组

将byte[]还原为图片:

byte[] b = ...//这里的b为上面生成的base64编码的byte数组
MemoryStream ms = new MemoryStream(b);
BitmapImage bitImage = new BitmapImage();
bitImage.SetSource(ms);
img2.Source = bitImage;