Badge / Rank How to Question?

[Fergal C]

I want to start giving recognition to helpful members on my forum, via a graphic in their PostBit. Basically if I decide that a particular member has been helpful to the community I want to display a graphic in their PostBit that says something like "Helpful Member".

Are User Ranks the best way of doing this?

If I have someone design a graphic for me, what should I ask for in terms of graphic size and file type?

Thanks!