"Is it possible that we can set the image size on image file ---"
Yes you can. (Short Answer)
Gory details, etc. (Likely more than you want to think about)
A picture has size in some measurement units-- Inches for example. Then it
also has a level of detail (resolution) described as pixels or perhaps DPI.
It also has a level of resolution or detail - 1024x768 for example
So, what you usually need is a combination of both.
Display - 72-96 DPI is commonly used resolution-- a common standard display
size might be 1024x768
Picture size is as desired, generally one that can be printed one or more
copies per 8 1/2-11 page. (3x3, 4x6, 5x7, etc)
Many of the printer drivers will allow you to set options to scale a
picture, or print multiple copies per page, scaling as necessary.
You might consider a pixel to be a blend of the RGB colors or an individual
dot of a color. The numbers can get a little messy, due to the way displays
work. Since a dot from the printing standpoint can correspond to a dot of
one color or a blended dot of multiple colors, or even multiple dots blended
together based upon color, position, and the amount of ink, it's better to
not dwell on the details.
Some photo editors are capable of changing the resolution and physical size
of a picture, as well as where it might be printed on a page. This gets
confusing, since a picture has a finite number of details--pixels, dots,
whatever. A photo editor may reduce the detail level, and the number of dots
in a file. Or, by filling in pseudo dots, increase the number of dots in a
file. The file storing the picture may contain additional data that
contains a DPI setting, which has nothing to do with the number of pixels or
dots in the file. If present, within the capabilities of display and
printer software and drivers, the picture may be displayed or printed by
default in a size different than size and DPI settings within the file. If a
low detail/size file is scaled up to fill a page, the dots may be printed or
displayed such that individual color dots are easily noticed.
Display drivers and windows tend to use DPI settings that are related to
standard display resolutions (Pixels).
Printers can use a wider range, from around 200-300 DPI to maybe 4800 DPI.
From this point things start getting more complicated, since color printers
can overlap dots of different basic colors and size to produce colors and
tints. (The exact process used by a specific printer is usually a trade
secret, and involves data processing/modification within the printer
driver.) Data sent with out processing to the driver in printer specific
form may limit the printer to a lower resolution than you might expect.
(360 or 720 vs 4800 for example.)
Just to add more complication to the printing process with ink and bubble
jet printers, general practice is to have the driver use nozzle patterns in
a way to minimize heating of adjacent nozzles, control the blending and
drying process, and increase the printers resolution. A printer might have
hundreds of individual nozzles spread across three, five or six colors, plus
black and maybe a light black, relatively few nozzles are fired at one time.
Close placement of the many nozzles also allows higher precision in the
positioning of printed dots, reduces possible "banding", and also reduces
the number of steps needed to position the paper for printing.
