Photoshop resizes the image to 'fit' the working window for display only. It
does NOT alter the actual image.

Take and use the 'zoom' controls to set the images to 100% each and you'll
see the difference!

The CAMERA is insisting they are all 'sized' for 72dpi, not photoshop! Bad
Camera !!!

Yea - mine does that too. 72 dpi is only relevant if you also look at the
image size. If you look at the sizes of your 9 images, the higher 'quality'
ones should be bigger (have more pixels - or inches - whatever incriment you
are using).  The "dpi" really refers to the method of output/viewing of your
image - not the resolution.

-- 72dpi (dots per inch) is the resolution of your computer monitor. So for
every square inch that you see on your computer monitor, you are seeing
72x72 pixels.  This will never change....

-- Imagine that you have a single image that is 72x72 pixels.  Since your
computer monitor can only display 72dpi, your image will be 1" x 1"...

-- Your inkjet printer can print at a much higher resolution than your
monitor displays - 300dpi.  So for every square inch you see on a printed
page, there can fit 300x300 pixels.  That's about 4 times as many pixels in
an inch compared to the monitor. Now, if you take the above 72x72 pixel
image and print it on your 300dpi inkjet printer, your image will only be
about 0.25"x0.25" (one quarter the size displayed on your monitor)- because
you need 300x300 pixels to fill an inch - but you only have 72x72.

-- So the "DPI" refers to your output.  What maters is the actual "X" and
"Y" size of the image.  Your 3 megapixel camera can make an image of up to
2048x1536 pixels (approximately).  Your inkjet printer prints 300x300 pixels
in a square inch, so your printed picture will be 6.82 inches by 5.12
inches.  You see? - you have to print 2048 pixels accross the page - and can
fit 300 pixels in an inch - so 300 pixels times 6.82 inches = 2048.

- But your computer monitor displays only 72 pixels in an inch - so to
display all 2048 pixels (at 1:1 zoom - or 100%), you would need a monitor
that was 28.4 inches wide!  That's why digital camera images always look
HUGE on your monitor - unless you are zoomed out.  Photoshop will "Zoom to
fit" the image when you first open it.  If you are looking at your entire
image in photoshop, (double click the magnifying glass to see the image at
it's true 100% or 1:1 size.  Of course, zooming in our out of the image in
photoshop does not affect the actual resolution of the image - just the way
you see it.

That's probably because you are looking at them all way zoomed out - so you
can't see the detail.  Notice the status bar just above your image - it
probably says something like "1:3" or "1:4".  When you double click the
magnifying glass tool, you will be looking at it 1:1 - or 100% size.  If you
do this, you will see that some images are bigger (have more pixels) than
others.  The more pixels you have, the larger an image you can print or view
at 100% or 1:1.  Now you can always take an image with fewer pixels and
artificially blow up the size with your software or print settings, but then
you run into the problem we discussed at the begining of this thread.

Right.  more pixels takes more memory.  Let's imagine that your camera does
the following:

Low Quality Image = 640x480 pixels
Medium Quality = 600x800 pixels
High Quality = 2048x1536 pixels

If you compare the high quality and the low quality images (both at 100% or
1:1 - this is important) - you should see a considerable difference in the
detail.  If you are zoomed out on the images, you won't notice the
difference as much.  If you print both images on your inkjet (again, each at
100%) high quality will be bigger than the low quality.  If you take the low
quality image and artificially blow it up,  the quality of the image will
not be as good as if you used high quality image - because there's not as
much pixel information for a good image.

OK - going to cook dinner now ;-)