There two huge photographic malls in Shanghai, one in the vicinity of the central railway station (South entry, not very easy to find), the other one is called "Xing Guang" and can be found quite easily: Take the Metro line 8 to the station "South Xi Zang Road", the Mall is at the crossroads of Lu Ban Road and Xie Tu Road. Besides a whole log of digital things, you can also find films (kodak, Fuji, Lucky, etc.).

Forget C41 development, it's a mission impossible to find a store with adequate quality, because 99.9% of the people is shooting digital now.