把图片转换成二进制--把二进制转换成图片

From: http://www.cnblogs.com/yinluhui0229/archive/2012/09/04/2671037.html

private void button1_Click(object sender, EventArgs e)
{
	string path = this.textBox1.Text;
	byte[] imgBytesIn = SaveImage(path);
	ShowImgByByte(imgBytesIn);
	//Parameters.Add("@Photo", SqlDbType.Binary).Value = imgBytesIn;

}
//将图片以二进制流
public byte[] SaveImage(String path)
{            
	FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read); //将图片以文件流的形式进行保存
	BinaryReader br = new BinaryReader(fs);
	byte[] imgBytesIn = br.ReadBytes((int)fs.Length);  //将流读入到字节数组中
	return imgBytesIn;
}
//现实二进制流代表的图片
public void ShowImgByByte(byte[] imgBytesIn)
{
	MemoryStream ms = new MemoryStream(imgBytesIn);
	pictureBox1.Image = Image.FromStream(ms);
}

二、将图片保存到数据库中，并从数据库中读取：

#region 将图片从数据库中读取
/// 

/// 将图片从数据库中读取
/// 
/// 要读取图片的学号
/// pictureBox1控件名
public void get_photo(string xs_ID, PictureBox ph)//将图片从数据库中读取
{
	byte[] imagebytes = null;
	getcon();
	SqlCommand con = new SqlCommand("select * from S_jiben where S_num='" + xs_ID + "'", link);
	SqlDataReader dr = con.ExecuteReader();
	while (dr.Read())
	{
		imagebytes =(byte[])dr.GetValue(18);
	}
	dr.Close();
	con_close();
	MemoryStream ms = new MemoryStream(imagebytes);
	Bitmap bmpt = new Bitmap(ms);
	ph.Image = bmpt; 
}
#endregion
#region
public void SaveImage(string MID, OpenFileDialog openF)//将图片以二进制存入数据库中
{
	string strimg = openF.FileName.ToString();  //记录图片的所在路径
	FileStream fs = new FileStream(strimg, FileMode.Open, FileAccess.Read); //将图片以文件流的形式进行保存
	BinaryReader br = new BinaryReader(fs);
	byte[] imgBytesIn = br.ReadBytes((int)fs.Length);  //将流读入到字节数组中
	getcon();
	StringBuilder strSql = new StringBuilder();
	strSql.Append("update S_jiben Set xs_photo=@Photo where S_num=" + MID);
	SqlCommand cmd = new SqlCommand(strSql.ToString(), link);
	cmd.Parameters.Add("@Photo", SqlDbType.Binary).Value = imgBytesIn;
	cmd.ExecuteNonQuery();
	con_close();
}
#endregion