iOS/Android(?): Show sync activity

At the moment, sync activity is not visible in the Picture-View, only in the Settings-Screen. Maybe one can see the running sync process for the current object (picture/video), but if that object is not on the screen, the user cannot see, if the sync process is running.
Idea: show sync activity e.g. as a circling sign around the profile/settings button. Or as a progress bar around the icon. Or a small string “sync in progress” with a moving background progress bar (background color grows from left to right). As soon as the synchronization is done, the string disappears.