There were cable cars on Market Street until the 1906 earthquake and fire; after that, there were streetcars. This card was sent in 1912, and the picture shows the new Palace Hotel, built in 1909. The original 1887 Palace Hotel was destroyed by a fire following the earthquake. That means these would be the new trolley cars not cable cars.
And here are some pictures of the original Palace Hotel and the new Palace Hotel.
Here's the back of the first card, sent to Jack Keegan in Portland, Oregon.:
Frisco 11/3 -12
Regards to you and yours from me and mine. Best remembrances to "Chubby" and rest of bunch. always be sure your eggs are hard boiled. Tell C. Johnson that the D. & R. G. have grand offices in Frisco. The cubs (?) at Garibaldi Hall were asking for you
(Note: I think the D. & R. G. refers to the Denver & Rio Grande Railroad)