Quote: "First question: is it possible to use expansion files with png, obj, all file types, or can we store in expansion files only video files?"
Last i have heard only thing you may store in expansion files is videos.
Quote: "Second question: could someone supply a short how-to, sample, hints, etc about how to use expansion files?"
Last time i heard Paul say anything about Expansion files was avoid if possible (as there is no short how-to sample to provide. things get complicated and ugly)
The only option you would have at the moment is retrieving media via the internet...Having your media uploaded to your website and downloading it into your media folder the first time the app has been run.
^ I have not done this myself but have heard others talk about it.
Beta Test Age of Knights:https://play.google.com/apps/testing/com.CrazyProgrammerProductions.my_AgeOfKnights
Download JellyFish Dive:https://play.google.com/store/apps/details?id=com.CrazyProgrammerProductions.my_JellyFishSwim