wmf screen resolution problem!!!

Dear colleagues,

For the past two weeks we have been struggling to create a proper image
with stable pixels, height & width from R for various screen resolutions.

We are trying to generate a wmf image with fixed pixels, fixed height &
fixed width. But the problem we are facing is that when the same code is

run on a different screen resolution the dimensions of the image are no
longer the same.

We would like to generate an image with height=16.6 cm and width=25 cm.
Example code:
##Width & height in inches
height <- 6.53
width  <- 9.84
h <- height + (height*0.128)  #Correcting the height so that when inserted
into word doc height in the Original size is 16.6cm
w <- width  + (width*0.0570) #Correcting the width so that when inserted
into word doc width in the Original size is 25cm
win.metafile("path to save\\test.wmf", height=h, width=w, restoreConsole =
TRUE)
boxplot(1:100)
dev.off()

When this image is generated on a screen resolution
*1280x1024* ==> height =16.6cm   ; width=25cm   ;  pixels=999x708
*1920x1080 *==> height =15.73cm ; width=16.6cm ; pixels=999x708

Is it possible to keep all the 3 things fixed across different screen
resolutions?

Please find attached the images generated in the 2 resolutions.

It would be of great help if anyone could suggest what could be done.

Thanks in advance!!!

Regards,
Karthik