iPhone 6 and yellow cast images when posting to FB

[pizellie]

I have posted images to FB with success - as good as FB renders them.

I have recently seen that when my photos are "saved as" and then reposted on FB, they are very heavy in a yellow case and saturation.

Since the original images are okay, I am suspecting that there is a setting on the person's iPhone that is causing this highly saturated yellow case.

Any thoughts/solutoins?