Could not get pixel color from jpg picture

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C#3.5

Hellow
i am trying to get the color of pixels of a string using c sharp program
the string is created in paint brush program and equal +-1234567890
in paint brush i selected text (the big capital A icon)and choosed black as a foreground color on white background the size of text was 16
then i wrote +-1234567890
and saved it in file named MyNumbers.jpg
in the program below i could not find the black color which was made in paint brush program
the purpose of my program is to store (in file)the black pixels(the foreground) as 1 and the white pixel(the background) as 0
i could not do that
the following is the complete program ... please help

What I have tried:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
namespace ScalImage
{
    public partial class Form1 : Form
    {
        public  FileStream fsw;
        public  StreamWriter sw;
        //----------------------------
        Pen p;
        int x, y;
        int start_x, start_y;
        Bitmap _bmp;
        Color co;
        PictureBox MyPictureBox1;
        Graphics gr;
        public Form1()
        {
            InitializeComponent();
        }
        private void FormLoad(object sender, EventArgs e)
        {
            fsw = new FileStream("MyDebug.txt", FileMode.Truncate, FileAccess.Write);
            sw = new StreamWriter(fsw);
            //-------------------------------------------
            MyPictureBox1 = new PictureBox();
            p = new Pen(Color.Red, 1);
            //-------------------------------
            MyPictureBox1.Parent = this;
            MyPictureBox1.Enabled = true;
            MyPictureBox1.Left = 1;
            MyPictureBox1.Top = 1;
            MyPictureBox1.Width = 160;
            MyPictureBox1.Height = 64;
            MyPictureBox1.Image = Image.FromFile("MyNumbers.jpg");//"MyNumbers.bmp");//"MyNumbers.gif");
            MyPictureBox1.Show();
            //-----------------------------------------------------
            _bmp = new Bitmap(MyPictureBox1.Image, MyPictureBox1.Size);
            //Graphics objGraphics = Graphics.FromImage(_bmp);
            gr = this.MyPictureBox1.CreateGraphics();
            textBox1.Text = MyPictureBox1.Width.ToString();//ReadOnly
            textBox2.Text = MyPictureBox1.Height.ToString();//ReadOnly
        }
        private void button1_Click(object sender, EventArgs e)
        {
            int f1,f2,f3;
            for (y = 1; y < MyPictureBox1.Size.Height; y++)
            {
                for (x = 1; x < MyPictureBox1.Size.Width; x++)
                {
                    co = _bmp.GetPixel(x, y);
                    //sw.Write(pixelColor[x, y].R.ToString()+","+ pixelColor[x, y].G.ToString()+","+  pixelColor[x, y].B.ToString()+" ");
                    f1=0;  f2=0;  f3=0;
                    if (co.R != 255 ) f1=1;
                    if (co.G != 255 ) f2=1;
                    if (co.B != 255 ) f3=1;
                    ;
                    if(f1==1 && f2==1 && f3==1)  sw.Write("1");
                    else sw.Write("0");
                }
                sw.Write("\r\n");
            }
            start_x = int.Parse(textBox3.Text);//you may need this
            start_y = int.Parse(textBox4.Text);//you may need this
            gr.DrawLine(p, start_x, start_y, start_x + MyPictureBox1.Width, start_y);//you may need this
        }
        //-----------------------------------------
        protected override void OnClosing(CancelEventArgs e)
        {
            if (sw != null) sw.Close();
            if (fsw != null) fsw.Close();
        }
        //-----------------------------------------
     }
}