Which laptop is best for me? Samsung series 9 or series 7?

Im trying to decide between the series 9 and series 7. Most likely 15.6 inch. I like that the 9 is compact but 7 is powerful. I use my computers mostly for photo editing and some MMORPG (online) gaming. So the quality of graphics and screen is important as well as being able to multi-task. Ill also be attending university next year and would like something that can keep up and not die on me.