ขอคำแนะนำ การหา pixel ของภาพครับ ควรเริ่มจากตรงไหนดี

private void GetPixel_Example(PaintEventArgs e)
{

    // Create a Bitmap object from an image file.
    Bitmap myBitmap = new Bitmap("Grapes.jpg");

    // Get the color of a pixel within myBitmap.
    Color pixelColor = myBitmap.GetPixel(50, 50);

    // Fill a rectangle with pixelColor.
    SolidBrush pixelBrush = new SolidBrush(pixelColor);
    e.Graphics.FillRectangle(pixelBrush, 0, 0, 100, 100);
}

Private Sub GetPixel_Example(ByVal e As PaintEventArgs)

    ' Create a Bitmap object from an image file.
    Dim myBitmap As New Bitmap("Grapes.jpg")

    ' Get the color of a pixel within myBitmap.
    Dim pixelColor As Color = myBitmap.GetPixel(50, 50)

    ' Fill a rectangle with pixelColor.
    Dim pixelBrush As New SolidBrush(pixelColor)
    e.Graphics.FillRectangle(pixelBrush, 0, 0, 100, 100)
End Sub