Image size / quality

I thought somehow it would be a good idea to get as high a megapixel camera
as I could and I've just got a Sony DSC-P10. In fine mode I get a huge
picture. Can anyone tell me how to maintain quality but reduce the full
image size to say 10 x 8 inches? I'm using Photoshop and the original
picture is only 72 pixels/inch.

 

Final image size has little to do with the displayed image size. You
can take a half megapixel image and print it poster size or take an 11
megapixel size image and print it display it as a 1x1.5 inch image.

The problem with doing the first is that the resulting image will not be
too clear, and in the second you will be using a large clumsy file when a
much smaller easier to use file would work better.

There are a number of ways or reducing the file size after the fact,
which if you want to display the image on a monitor is often a good idea as
the smaller size will display quicker and will open the intended size most
of the time. Photoshop will allow that change.

BTW "72 pixels/inch" has nothing to do with the original file or image.
It is a measure of the way a image is printed or displayed, but not the
file. I can print a 100 meg file at 72 pixels/inch to an 8x10 or I can print
a 0.1 meg file at 72 pixels/inch to an 8x10.

 

If you're using a recent version of Photoshop or Elements, when you've selected
your paper size from the printer driver selection, you can then get Photoshop to
"fit to paper", and you'll get your 10" x 8" print or whatever.
In earlier versions such as 5LE, go to Image, Image Size, and untick the
"Resample Image" box. You can then play with pixels/inch until you get the size
you want. This leaves your original file intact. If you resample, you will be
throwing your original away.

 

In most software the initial setting of ppi is a default value. First of
all, you need not use the default value. If you select printing at any
other physical size, and do not resample, it will change PPI.

Second, most software that has a default setting for PPi also have ways
of changing the default, under something like the preferences menu.
Don't know menu exactly on PS (I don't use it) but cannot believe the
default is not changable with proper setup.