Canon Elph Cameras

Series A and Canon Digital ELPH?

First, what is the difference between series A Canon Digital ELPH? On the other hand, This is an ELPH camera?

size and function is the difference goes canonusa.com SD Series cameras are ELPH

1997 commercials: Sears, Taco Bell (Batman & Robin Unmask Sweepstakes), ELPH cameras (Canon), Schick