If you want to switch from using the basic skin data to the full skin data (including player pics) or vice versa, just re-install the game.
§ Launch the Google Play Store app from your home screen or app drawer.
§ Tap the search bar at the top of the screen.
§ Type Football Manager Mobile 2018.
§ Tap on the installed app.
§ Tap Uninstall.
§ Tap OK to confirm uninstall.
§ From the Google Play Store app.
§ Tap Menu followed by My Apps and games followed by Library.
§ Tap the app you want to install.
§ Tap Install.
§ On running the game you will be prompted to re-download the data