In the event no one can access the internet and cannot download and install Jami, it would be great if the Jami apps themselves (Android, Windows, Mac & Linux) each contained the latest version of the Jami APK, EXE, DMG and a Linux AppImage which can be saved to your device storage and then you can share the files with others to install and start using Jami.
Or if every time you install Jami or update Jami, a popup in the app will appear requesting the user to download the latest Jami APK, EXE, DMG and a Linux AppImage in the event others cannot access the internet to install Jami. The download links can be a direct download of the APK, EXE, DMG, AppImage and a torrent download option of the APK, EXE, DMG, AppImage.
The second option will be easier to implement and keep the app size smaller since the APK, EXE, DMG, AppImage is not embedded into the other clients and therefore downloading and installing Jami will still be the same size that it roughly is and not 5x larger in size. Either option will keep Jami clients distributed across every Jami user to ensure as many people as possible can have access to the Jami apps when the internet is restricted or down.
To my understanding Jami is not released as an AppImage option and I think it should be since AppImages are portable Linux applications that work on any distro.