C#中，如何从Image对象得到FileStream

using System.Runtime.Serialization.Formatters.Binary;

BinaryFormatter formatter = new BinaryFormatter();

System.IO.MemoryStream ImageStream = new System.IO.MemoryStream();

formatter.Serialize(ImageStream,pictureBox1.Image);

BinaryReader reader = new BinaryReader(ImageStream);

byte[] mBytes = new byte[ImageStream.Length];

reader.Read(mBytes,0,mBytes.Length);

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BinaryFormatter formatter = new BinaryFormatter();

Stream ImageStream = new System.IO.MemoryStream();

formatter.Serialize(ImageStream,pictureBox1.Image);

//BinaryReader reader = new BinaryReader(ImageStream);

byte[] mBytes = new byte[ImageStream.Length];

ImageStream.Position = 0;

ImageStream.Read(mBytes, 0, (int)ImageStream.Length);

ImageStream.Close();

Stream wFileStream = new System.IO.MemoryStream();

//BinaryWriter writer = new BinaryWriter(wFileStream);

wFileStream.Write(mBytes,0,mBytes.Length);

wFileStream.Position = 0;

pictureBox2.Image = (Image)(formatter.Deserialize(wFileStream));

//writer.Close();

wFileStream.Close();

//wFileStream.Close();