关于流的操作,该怎么解决

关于流的操作
VB.NET code

Dim ms As New IO.MemoryStream
PictureBox1.Image = Image.FromStream(ms)


这样可以把流写入图片控件,那反过来把图片控件中的图片写入流,该怎么做?

------解决方案--------------------
Dim s As IO.Stream
Dim img As Image
img.Save(s, System.Drawing.Imaging.ImageFormat.Bmp)