I have this anime on DVD along with the 
`conte` (drawings, sketches, etc.)disk. I doubt 
that it was digitally created except for perhaps 
a scene or two. I also have this link to an 
interview from Ghibli Studios, taken by 
Miyazaki Hayao himself stating his disinterest 
in using CG concerning Sen to Chihiro. He 
does admit to using it once or so but not on 
characters.

But, I could be wrong ^-^. I hope that I am right 
though.

Here is the link above to the interview. If you 
cannot read Japanese you might cut and 
paste it into a translation program.

E.