The new OS X Photos App allows to hide photos. Hidden photos will only appear in the
Hidden album (or in any album which you explicitly added them to).
However, the Hidden photos keep showing on the iOS Photos App. iOS detects they are hidden, but it merely hides them from the image picker controller on third party apps. They can still be viewed in the main Photos App on the All Photos section. Is there any way to hide them from All Photos as well?