The encoded image data is horizontally flipped and rotated 90° clockwise from the image's intended display orientation.
Mac Catalyst 13.0+
The (x,y) pixel coordinates of the origin point (0,0) represent the bottom row and rightmost column, respectively. Pixel (x,y) positions increase bottom-to-top, right-to-left.
If an image is encoded with this orientation, then displayed by software unaware of orientation metadata, the image appears to be horizontally mirrored, then rotated 90° clockwise. (That is, to present the image in its intended orientation, you can rotate 90° counter-clockwise, then flip horizontally.)