[smackfu]

The theory is that you have the image off the sensor, and then you have metadata about the image in the EXIF fields. The debatable point is whether orientation should be treated as metadata or is inherent to the image data. On early digital cameras, this wasn't so debatable since adding an orientation sensor was a deluxe feature that really did just add another bit of data to the photo.

[jstanley]

But the JPEG file doesn't contain the image off the sensor. That is what "RAW" images are.

[smackfu]

Sorry, meant the image off the image processor, which has already processed the raw data into a grid of RGB.