image orientation on the screen

[Mike Newberry]

Since there is no hardwired spec and no keywords for this, I wonder if
there is a commonly adopted "standard":

Where should pixel (0,0) of a FITS file be displayed on the screen-- in
the upper left or lower left corner? And for which ever is correct,
should the screen image match the orientation (i.e., no mirror reversal)
of what the CCD saw?

Mike Newberry