How to take a snapshot in Google Map v2

// Once everything has loaded, cache the map’s image for fast display later
// Note: the map loaded callback is only called once.
mMap.setOnMapLoadedCallback(new GoogleMap.OnMapLoadedCallback() {
    public void onMapLoaded() {
        mMap.snapshot(new GoogleMap.SnapshotReadyCallback() {
            public void onSnapshotReady(Bitmap bitmap) {
                // Write image to disk
            }
        });
    }
});

Reference: http://googlegeodevelopers.blogspot.sg/2013/10/ghost-markers-in-your-neighborhood-new.html