MBP Graphics card 256 or 512mb

hi, im looking to get a macbook pro for college where i will be majoring in photography. I have a 2.16 imac stock already and play call of duty 4 on in occasionally and it works fine for that. My question is, when i purchase the MBP, will i notice a difference between the graphics card in the Base MBP or the 2.5 with the 512mb graphics card? the hard drive space is not a question because i have externals, but i was just wondering if i could possibly save myself $500. this is my first post so sorry if its the wrong section.

 

yeah i just realized i should have searched before but i forgot sorry. thanks for the replies