void Fun(Image image)
{
               MemoryStream ms = new MemoryStream();
               image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
               bytes = StreamToBytes(ms);
               Stream ms2 = BytesToStream(bytes);
                if (Form == null)
               {
                   Form = new Form2();
                   Form.pictureBox1.Image = Image.FromStream(ms2);//参数无效
                   Form.ShowDialog();
               }
}
 private byte[] StreamToBytes(Stream stream)
        { 
            byte[] bytes=new byte[stream.Length];
            stream.Read(bytes, 0,bytes.Length);
            stream.Seek(0, SeekOrigin.Begin);
            return bytes;
        }
 private Stream BytesToStream(byte[] bytes)
        {
            Stream stream = new MemoryStream(bytes);
            return stream;
        }