The background is only going to make a difference because of the camera mode.
If you light the subject correctly and the same in both settings and set the white balance, you can get the same results.
That said, I COMPLETELY understand your point in how to perceive photo in ads. You are right on. Most people use a point and shoot on auto and the photos will vary dramatically.
Also, there is a big difference from monitor to monitor that most poeple don't realize.
Great snake.
(nice photos too.)