Text Alignment problem in picturebox...

Image bac;
Bitmap myBitmap;
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
            if (mybitmap == null)
            {
                mybitmap = new Bitmap(pictureBox1.Width, pictureBox1.Height, pictureBox1.CreateGraphics());
 
            }
 
            rect = new Rectangle(e.X, e.Y, 0, 0);
             this.Invalidate();
 
}
 
 
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
 
 
               switch (e.Button)
      {
                case MouseButtons.Left:
           {
                    rect = new Rectangle(rect.Left, rect.Top, e.X - rect.Left, e.Y - rect.Top);
                    this.Invalidate();
 
                break;
            }
 
       }
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
 
            if (mybitmap == null)
            {
                return;
            }
            using (Pen pen = new Pen(Color.Red, 2))
            {
                using (Graphics g = Graphics.FromImage(mybitmap))
                {
                e.Graphics.DrawRectangle(pen, rect);
 
                 if (label1.TextAlign == ContentAlignment.TopLeft)
                    {
                        e.Graphics.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), label1.Bounds); 
                        g.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), label1.Bounds);
mybitmap.PixelFormat);
                    }
                    else if (label1.TextAlign == ContentAlignment.TopCenter)
                    {
                        SizeF size = e.Graphics.MeasureString(label1.Text, label1.Font);
                        float left = ((float)this.Width + label1.Left) / 2 - size.Width / 2;
                        RectangleF rect1 = new RectangleF(left, (float)label1.Top, size.Width, label1.Height);
                        e.Graphics.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), rect1);
 
                    }
                    else
                    {
                        SizeF size = e.Graphics.MeasureString(label1.Text, label1.Font);
                        float left = (float)label1.Width - size.Width + label1.Left;
                        RectangleF rect1 = new RectangleF(left, (float)label1.Top, size.Width, label1.Height);
                        e.Graphics.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), rect1);
                    }
 
               }
 
        }
 
}
 
private void saveToolStripMenuItem_Click(object sender, EventArgs e)
{
 
 
            if (mybitmap != null)
            {
                SaveFileDialog SaveFD1 = new SaveFileDialog();
                SaveFD1.FileName = "";
                SaveFD1.InitialDirectory = "C";
                SaveFD1.Title = "save file Name";
                SaveFD1.Filter = "JPG|*.jpg|Bmp|*.bmp";
                 if (SaveFD1.ShowDialog() == DialogResult.OK)
                {
 
                    System.IO.Stream filename = (System.IO.FileStream)SaveFD1.OpenFile();
 
                    int r = SaveFD1.FileName.Length;
                    for (int r1 = 0; r1<=r;)
                    {
                        if (SaveFD1.FileName[r1] != '.')
                            r1++;
                        else
                        {
                            r = r1;
                            break;
                        }
                    }
 
                       if (SaveFD1.FileName[++r] == 'j')
                        {
                            using (Graphics g = Graphics.FromImage(bac))
                        {
                           g.DrawImage(mybitmap, 0, 0);
                        }
                        bac.Save(filename, ImageFormat.Jpeg);
                        }
                        else if (SaveFD1.FileName[r] == 'b')
                        {
                            using (Graphics g = Graphics.FromImage(bac))
                            {
                                g.DrawImage(mybitmap, 0, 0);
                            }
                            bac.Save(filename, ImageFormat.Jpeg);
                        }
                        else
                        {
                            using (Graphics g = Graphics.FromImage(bac))
                            {
                                g.DrawImage(mybitmap, 0, 0);
                            }
                            bac.Save(filename, ImageFormat.Png);
                        }
 
                    filename.Close();
 
                }
            }
        }
 
private void openToolStripMenuItem_Click(object sender, EventArgs e)
{
 
            OpenFD.FileName = "";
            OpenFD.Title = "open image";
            OpenFD.InitialDirectory = "C";
            OpenFD.Filter = "JPEG|*.jpg|Bmp|*.bmp|All Files|*.*.*";
            if (OpenFD.ShowDialog() == DialogResult.OK)
            {
                file = OpenFD.FileName;
 
                bac = Image.FromFile(file);
                pictureBox1.Image = bac;
                pictureBox1.Invalidate();
 
 
            }
 
        }

//in save tool tip
if (SaveFD1.FileName[++r] == 'j')
                        {
                            bac = pictureBox1.Image;
                            //bac = mybitmap;//no problem if I use this
                            using (Graphics g = Graphics.FromImage(bac))
                            {
                               g.DrawImage (mybitmap,0,0);
 
                            }
                            bac.Save(filename, ImageFormat.Jpeg);