The Bitmap class's RotateFlip method makes it easy to rotate an image by a multiple of 90 degrees and flip it vertically or horizontally. This example wraps the call to RotateFlip in the following ModifiedBitmap method. It makes a copy of an image, rotates and flips the copy, and returns the result.

// Copy the bitmap, rotate it, and return the result.
private Bitmap ModifiedBitmap(Image original_image, RotateFlipType rotate_flip_type)
{
    // Copy the Bitmap.
    Bitmap new_bitmap = new Bitmap(original_image);

    // Rotate and flip.
    new_bitmap.RotateFlip(rotate_flip_type);

    // Return the result.
    return new_bitmap;
}

The following code shows how the program calls this method to rotate the image 180 degrees and then flip it horizontally:

private void rad270FlipX_CheckedChanged(object sender, EventArgs e)
{
    picResult.Image = ModifiedBitmap(
        picOriginal.Image, RotateFlipType.Rotate270FlipX);
}

After rotating or flipping a Bitmap, you can use its Save method to save the result into a file.