数据库读取和保存图片
//从数据库读取图片，并保存为11.jpg
using (SqlConnection vConn = new SqlConnection(mConnStr))
        {
            vConn.Open();
            using (SqlCommand vCmd = new SqlCommand("select picture from tbUsers", vConn))
            {
                SqlDataReader dr = vCmd.ExecuteReader();
                if (dr.Read())
                {
                    byte[] photo = dr[0] as byte[];
                    FileStream fs = new FileStream(Server.MapPath("~/11.jpg"), FileMode.CreateNew);
                    fs.Write(photo, 0, photo.Length);
                    fs.Close();
                }
                dr.Close();
            }
        }
//保存图片到数据库
FileStream fs = new FileStream(@"E:\1.jpg", FileMode.Open, FileAccess.Read);
        BinaryReader rd = new BinaryReader(fs);
        byte[] vPhoto = rd.ReadBytes((int)fs.Length);
rd.Close();
        fs.Close();
        using (SqlConnection vConn = new SqlConnection(mConnStr))
        {
            vConn.Open();
            using (SqlCommand vCmd = new SqlCommand("insert into tbusers(username,picture) values(@username,@picture)", vConn))
            {
                vCmd.Parameters.Add(new SqlParameter("@username", "张三"));
                vCmd.Parameters.Add(new SqlParameter("@picture", vPhoto));
                vCmd.ExecuteNonQuery();
            }
        }