The big sleep- movie vs book

In my opinion, I prefer the book compare to the movie because as I read the novel, I get to imagine things in the way Mr. Marlowe was describing the investigation, and things around him. However, the movie didn't show a lot of the books description. For example, in the book Mr. Marlowe describes General Sternwood h as a "The rest of his face was a leaden mask, with the bloodless lips and the sharp nose and the sunken temples and the outward-turning earlobes of approaching dissolution. His long narrow body was wrapped-in that heat-in a traveling rug and a faded red bathrobe. His thin clawlike hands were folded loosely on the rug, purple-nailed. A few locks of dry white hair clung to his scalp, like wild flowers fighting for life on a bare rock." In other words,  Marlowe describes General Sternwood as a man who will die at any moment but the movie shows Mr. Sternwood as a old man on the wheelchair, that needs to know who is blackmailing him. But overall of the movie is okey.