In article , JimG
wrote:

I am a recent Canon T2i owner and am comparing metadata information reported
in Adobe Bridge with photos taken with my P&S Canon A640. Bridge reports
the resolution of the T2i photos as 72 ppi while the A640 are reported as
180 ppi. Both cameras were set to record images as "large jpeg". I
realize that the cameras have different sensors and will have different,
overall pixel dimensions but why are the ppi different? Is ppi density a
setting on the T2i? I realize that Windows computer monitors display at 72
dpi.

pixels per inch only matters when you print. cameras write various
values in that field and it makes no difference except to a couple of
page layout apps. it's easily changed, and doesn't actually change the
number of pixels.

what matters is the total number of pixels, which won't change unless
you upsize or downsize.