Recently, Apple made it so that applications had to ask you for permission to track you. Facebook was especially hit hard.
And, as this article notes, if you upload photos with normal embedded data…they can still track you:
Facebook Is Circumventing Your Privacy Settings, But You Can Stop Them
On the last day of April, Apple released a privacy-enhanced version of its popular mobile operating system for iPhone and iPad — and Facebook is already working hard to bypass those new privacy...
The article also shows you where you can turn off allowing the apps to even ask you, so it’s worth a read.