Emi_Brooke,
if your new MacBook Pro is the non-Retina model, then you can upgrade its RAM if you decide that you’d like to have more installed. If your new MacBook Pro is a Retina model, then you’re out of luck — you’ll have to live with whatever you first buy. Regarding your immediate questions, if you will not be editing your photos, but just storing and viewing them, then the amount of disk will be more important than the amount of RAM. If you want to play games, then you should pay close attention to the system requirements of whichever games you would like to play, so that you don’t try to play games for which you have insufficient RAM.