*pokes her head in one more time to be 
obnoxious* hehe

actually, the backgrounds were handpainted 
just like the cels.  Only a few scenes in the 
Disney movies you are talking about had any 
CG backgrounds.  The Little Mermaid may 
have had one CG background.

Beauty and the Beast, the backgrounds were 
all still hand painted even though there were 
no cels being painted (the characters were 
computer colored, but hand drawn.).  with the 
exception of the ballroom scene of course 
where the background was computer 
generated wholy.

In the Lion King, still most of the background 
were hand painted, with a small exception.

Tarzan was the first Disney feature to 
extensively feature computer generated 
backgrounds in a good portion of shots (alot 
of those vines and trees were 3d "wrapped" 
with hand painted textures, etc, to allow Tarzan 
to do "live action" kind of camera moves)