You can`t, sorry, I lost it.
But here's a good idea for a scrolling engine, using big images:
Have a
cam_x, cam_y, cam_w, cam_h
cam_w = 320 (screen res x)
cam_h = 240 (screen res y)
cam_x = 0 ( starting position, gets increased )
cam_y = 0 ( horizontal scrolling )
bgimage = loaded...