PC for my friend

Hey so my buddy wants me to build him a pc instead of spending a small fortune on a mac. So he wants sort of an everyday type use pc with very light casual gaming and for some home photo editing when his wife starts a small business hobby as a photographer. 


So I'm wondering what sort of parts you would use for a pc like that without breaking the bank cause he still has to buy a monitor and what not.


Also for editing would you use windows 7 or windows 8.1?


Also what photo editing programs can you recommend for a noob?



Also would you go AMD or Intel for editing?

And his budget is 1000$