Mobile browser rotates images

My wife runs a small blog and uses an iPhone for a majority of her recipe photos. For an unknown reason, WordPress often rotates the picture (often square format). So she easily edits the image in the WordPress media module. That fixes the problem on desktop, but mobile display rotates the image back. I'm baffled and have only found a few inconclusive threads on the WordPress forums. http://keepingmysanity.com/chicken-enchiladas/