Somu told me some good info about these things when we were discussing
about the use of a 5 MP camera that I recently got.
Resolution of a photograph is something like 2500x1900 (ignore exact
number please), when we see it on a monitor with resolution of 1024x768 we
have to scroll to see the whole picture. Now when we print it on a paper
we will not get that big a photo as our monitor is( forget about the
scrolling part). Why?
Basically monitors have a dpi (dots per inch) value of something like 72.
That means if there are 720 dots they will be put in 10 inches. Now in our
photo case they are something like 2500 dots which will mean around 30
inches of view, so with a monitor of view size 14 inch we need to scroll
for another 16 inch to see the photo completely.
Now coming to case of a printer, the printer has a resolution(?) of around
300 DPI which is roughly 4 times that of a the monitor, that should mean a
2500 pixels which should give around 8 inches of photo print.
So you will not get more than 8inch by 6 inch photograph by a 5 MP camera.
Now its clear why ppl look for better resolution.