The image information page of the MAC shows only long + lat but not altitude...
You can also take a snapshot of your iPhone screen during flight which will show the altitude of the drone at the time the shot was captured and be stored with your photos on the mobile.
only relative to the take off point, you could combine this with the altitude of the take off point and edit the exif data (but you'd need to know the take off altitude (should be in the app)).