The orientation a picture has after the viewer turns it a quarter.
A turn composes with what the file already says rather than replacing
it, so a mirrored picture stays mirrored and four turns the same way
come back to the start. Quarter turns commute with each other but not
with the mirror, which is why only the turn count moves here.
The orientation a picture has after the viewer turns it a quarter.
A turn composes with what the file already says rather than replacing it, so a mirrored picture stays mirrored and four turns the same way come back to the start. Quarter turns commute with each other but not with the mirror, which is why only the turn count moves here.