I find it hilarious that so many people who have posted here are even attempting to place any meaning whatsoever into this film's imagery! The only point to be made in this movie is that there should be no point to be made. Any significance placed onto anything contained in this film is a complete fabrication of the narrow-minded viewer who believes movies are only made to carry some message. That is the genius of Bunuel and Dali. They were surrealists. The point of surrealism is that there is no point, no meaning whatsoever.
Personally, you all may dissect (pun intended) and pore over this great film if you please, but you are fools in the eyes of the (deceased) filmmakers for doing so.