将图片读到二进制

FileStream FStream = new FileStream(strImage, FileMode.Open, FileAccess.Read);
BinaryReader BReader = new BinaryReader(FStream);
byte[] byteImage = BReader.ReadBytes((int)FStream.Length);

将图片读到二进制

MemoryStream MStream = new MemoryStream((byte[])myds.Tables[0].Rows[0][2]);
pictureBox1.Image = Image.FromStream(MStream); //显示用户头像

从二进制读回图片