Explain in settings that downloading images works only if the option is enabled on the backend

I have spent way too much time trying to figure out why the app doesn't download images for offline use when this option is enabled, only to learn later that it also has to be enabled on the server.

I think it would be neat if the label for the setting of enabling downloading images on the client android app mentioned that this only works if this option is enabled on the server. Maybe even this option in the app could be greyed out if the feature is disabled on the backend?