Is it possible to remove unused files within my android app

I am currently programming an "One time after first login tutorial" and since it should be only shown one time after the user starts the application for the first time, I would like to remove all the unnecessary files like for example pictures which I only use in thi开发者_运维知识库s tutorial.

So is there a way to remove some of these files which are shipped within the .apk ?

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The Android apk is a read only file, so once a file is part of an apk, it cannot be removed.

An option would be to download the files from the network the first time the user installs the app and then put it on the sd card or locally and then delete it when you want it.