Does anyone knows, it is possible to add a automatic photo to FB timeline in certain year. For example, I have this app where user click a button, then automatically will post a photo in the year 1983. Does FB allow that to happen?
When publishing to the open graph, you can in fact set the time so that you can post a past event.
There's an official document/toturial for that, part of the Open Graph docs: Publishing Past Actions.
Hope this is what you're after.