In that case, take a look at that article. The long and the short of it is that if a digital photo is to be viewed on screen, if you're not going to be zooming in on a part of it, there is no point in it being larger in pixels than your display. So if you have a typical 1024x768 screen there is no point in your digital image being any bigger (i.e. approx 1 megapixel).