There are quite a few requests for flipping, which can also be set by editing the “orientation” EXIF tag by those who dare editing the raw file. It takes some experimenting to get things right.
I find this page to show orientation in a fairly comprehensive manner.
On a Mac, these commands help manage the orientation tag of a single image file
-
Show orientation tag: exiftool -Orientation -n /…path…/filename.ext
-
Set orientation tag: exiftool -Orientation=2 -n /…path…/filename.ext
-
Note: If the first command shows the tag to be 1, the second command sets the tag
so that orientation enabled apps will show the image horizontally flipped. -
The “-n” switch reports the value of the orientation tag numerically, without it, you can
get something like “Flip horizontally and rotate 270° CW”.
Caveat: DxO PhotoLab still can’t flip an image, even if you set the rotation tag accordingly.