Some graphic editors mess up with the orientation in the EXIF information. That’s the most common source of problems with orientation. Some don’t read the EXIF, some do read it but don’t update it when the image is rotated.
I tried to import a photo from my 4S, but it’s too big (> 2 MB). Did you resize them first in a graphic editor?
FWIW, I resized + rotated an image from my iPhone in Photoshop and the orientation was correct in Kirby.