There are 4 main
techniques to control file size.
The first is
cropping. This eliminates unneeded background. There is no effect on image
time you make changes on a jpeg you lose quality. Be it crop, resize or
The second is
setting pixels (dots) per inch (dpi). As was just pointed out,
monitors show either 72 or 96. What is shown on the monitor when the dpi is 300
or 600 depends on the software being used. Some software shows the entire image
at the monitor's dpi so the image is greater than the size of the monitor.
This is usually hated by the person who received the image. Other software
resizes the image so the image is just full screen. There can be image quality
impacts of the resizing.
web 72 dpi is all that is needed. More will not show on the monitor only at the
The third is image
size. In general, image quality decreases as image size
for viewing, small image size makes it harder to see picture. If the dpi is
large the information is there.
inch X10 inch 72 dpi photo is about as big as a 15"monitor can see without
scrolling. It will be around 70 kb in size.
The fourth is
compression. jpg is a compressed format. The jpg software can adjust the
compression ratio. The greater the compression ratio the less accurate the color
and detail. Considering the lack of color accuracy in the whole process of
obtaining and viewing an image, compressing an iris image to a file size about
50K will be totally acceptable to most of this group. Anyone who needs greater
quality can do so off line.
I have attached a
photo of a Peter Jackson Louisiana iris seedling to show what is possible
in terms of quality and size in a 63K file.
is a good size for me. It is 6½" X 6½" on my 17" monitor.
Fortunately I have
DSL and Windows XP so all of this discussion of file size has little
significance to me.
Wondering if I sent you a dozen 12 meg Tiff's if you would take that
However I do
remember the bad old days of dialup when I was quick to remind senders of large
files to be more considerate in the future.
one and it was for sending to many photos to a photo list. They were under 50
that I didn't make mistakes sending before resizing.
Personally I think a
restriction of 50K is too restrictive. When I was on a 44k dialup, I felt the
file size limit should have been 300K. Any comments from the dialupers on what
they feel is a reasonable limit. A change in the recommended file size may
be a reasonable compromise.
Trouble is Harold there are people out there that have 56 k modems with a
28 k connections. Their phone lines are the problem not their computers. 44k
connection is better than average. I believe a 75kb file would make a good