Okay so I'm supposed to write a report describing the classes and interfaces I will use to implement a popular online photo management system called flickr (http://www.flickr.com/). I don't need to implement any method but just figure out the design based on www.flickr.com/tour section of this site. I must have classes and interfaces.

I really am stuck and dont know where and how to start; any help would be appreciated.

oh i forgot to mention, all I have to do is make a UML of the design with classes/interfaces and method and variable names. no coding.