I have been looking for the fix for some time and saw this and it works. It was a real bind not being able to see the pictures but now I can !!
This tip came from BMWWorld.com
Watch TV / Videotext during driving
This works on all 5/7 Series with the Mk. I Navigation System (the one with the male voice). On Mk II (the newer version with the female voice) you have to use "brightness" instead of contrast for TV and "color" instead of brightness for videotext to get the trick to work. I know that the trick works on latest 99 7series models as well. But I heard also that some cars sold into the US do not have any TV equipment on board. You will notice this as they do not have any TV option in the main menu. Also latest BMWs sold in Europe (2000 onward, 3/5/7 series) have the trick disabled! The only chance to get the TV running is somewhere hidden in the menu of the BMW Sevice Tester DIS. But up to now I can't thell you where. If I ever find it out, I'll post it here!
As far as I know the software update for latest navigation CD Roms does not affect or disable this trick.
Set ignition to pos. II
enter TV mode
enter "settings"
enter "contrast"
when the green contrast bar is visible, push the knob and keep it pressed
turn ignition off (keep button pressed!)
wait 8-10 seconds (timing must be accurate!)
release the knob
turn on ignition again
Now you can watch TV during driving (but always keep at least one eye on the road - that said)
To watch videotext use the same procesure as above, but chose"brightness" instead of "contrast" (thanks to my friend Herbert Posner, who discovered this secret).