print image from picturebox wchich feet in A4 size paper

i want to print image in A4 size paper from picturebox on click on print button.

i have tried this , but when i will print this image on A4 size paper it cant print the hole image.

private void button1_Click(object sender, EventArgs e)

{

PrintDialog pd = new PrintDialog();

PrintDocument doc = new PrintDocument();

doc.PrintPage += Doc_PrintPage;

pd.Document = doc;

if (pd.ShowDialog() == DialogResult.OK)

doc.Print();

}

private void Doc_PrintPage(object sender, PrintPageEventArgs e)

{

Bitmap bm = new Bitmap(pictureBox1.Width,pictureBox1.Height);

pictureBox1.DrawToBitmap(bm, new Rectangle(0, 0, pictureBox1.Width, pictureBox1.Height));

e.Graphics.DrawImage(bm,0,0);

bm.Dispose();

}