It appears that, when you take a photo with the iPad, the current orientation of the device is taken into account. iOS handles this by always showing a photo 'top up'. Air doesn't!
So: take 2 photos with the iPad. The first one with the home button on the right (true landscape) and the second one with the home button on the left (reversed landscape). The 2 photos will show correctly in the photo app. When you import this photos using the camera roll class in Air however, the second photo will be upside down! How to check this??