private void button1_Click(object sender, EventArgs e)

        {

            string path = @"resim.jpg";

            Bitmap bmp = (Bitmap)Image.FromFile(path);

            bmp = ChangeColor(bmp);

            bmp.Save("resim1.jpg");

        }

        public static Bitmap ChangeColor(Bitmap scrBitmap)

        {

            Color newColor = Color.White;

            int genislik = scrBitmap.Width;

            int yukseklik = scrBitmap.Height;

            for (int i = 1; i < 215; i++)

            {

                for (int j = 0; j <190; j++)

                {

                    scrBitmap.SetPixel(genislik-i, j, newColor);

                }

            }

            return scrBitmap;

        }

 WebClient clientt = new WebClient();

 Stream stream = clientt.OpenRead(url);

 Bitmap bitmap; bitmap = new Bitmap(stream);

 bitmap = ChangeColor(bitmap);

 bitmap.Save("resimler\\resim.jpg");