Re:You are the one confused. (Score 1)

Yes, the DPI of an image is indeed valid when it comes to printing. Unfortunately some people in the business are so hooked up on these values they sometimes don't even know what they're asking for. At a webfirm I once worked, the firm's photographer and graphics artist once gave me this rather "no clue" request:

-"Scan these images so that they end up 72 DPI on my screen."