As Cees suggests buy a digital camera that is going to take excellent pictures first and foremost.
I recently bought a Cannon A40. 2.1 mp and it gives very good results. 2mp is the minimum but suggest you go for 3 or 4 mp for the extra money it would be worth it. The extra size gives you the option of cropping without loosing quality.
Most cameras come with a basic download & edit package with which to resize for your KN.

Graham UK