Bitmap bitmap1; private void Form1_Load(object sender, EventArgs e) { bitmap1 = (Bitmap)Bitmap.FromFile(@"D:\Screen01.png"); pictureBox1.SizeMode = PictureBoxSizeMode.AutoSize; pictureBox1.Image = bitmap1; } private void button1_Click(object sender, EventArgs e) { if (bitmap1 != null) { bitmap1.RotateFlip(RotateFlipType.Rotate180FlipY); pictureBox1.Image = bitmap1; } } RotateF..