I am launching my social network soon an looking into hosting. The question i am lost is: Do i need separate servers for web vs database vs image handling since there is photo sharing? Or does 1 server handle it all?

Also is more ram better? If i get 50GB ram is that better than having 8 gb ram?

EDIT: It is PHP codeignitor and MySQL for now. (switch to NoSQL DB later if demand calls fr it.) I will be using memcache also. Concept wise it is similar to yelp, so geographic based with lots of user content and image sharing + live feeds an privacy levels. User plan is open question. Without testing the demand for this i cant give a number. But the concept is unique, no one out there with the set of features i am releasing so it could grow. Ideally I want to plan for handling about 1-2 million views / month from launch. If it goes more than that then I will upgrade.