Photographer needs a Computer

My friend, a photographer in Bangalore, requires a computer to manage his images and to do post processing work. He also does play a few (older) games once in a while so something that can handle games like the earlier COD series is useful. His budget for this computer is around Rs 25,000.

Could you please suggest a good system that will fulfill all his requirements. The lower the price the better!

Thanks for any help/suggestions!