Gragphics.DrawImage on a flipped Image

[Steven]

I need to draw to an image after it has been rotated, but if I draw
something before the rotation is done then DrawImage doesn't work:

Here's the code.

using System;
using System.Drawing;

class ImageTest
{
public static void Main()
{
Image img = new Bitmap(67,98);
Graphics g = Graphics.FromImage(img);

//Without this line it works
g.DrawLine(new Pen(Color.Black), 0, 0, 67, 98);

//Width e Height are swapped
img.RotateFlip(RotateFlipType.Rotate90FlipNone);

g = Graphics.FromImage(img);
Image img2 = new Bitmap("test.bmp");

//img.Width is 98
g.DrawImage(img2, 80, 0);
img.Save("result.bmp");
}
}

The result of the code above is only a diagonal line.
If the call to DrawLine is removed, test.bmp is drawn too.
Please help.