Custom ImageViews not populating when using Picasso for Custom Marker InfoWindows in Maps

Question

I'm trying to use Picasso now for my Custom Marker's Images. I was previously using a Bitmap and setting individual Marker's InfoWindow Images with those Bitmaps with the help of a HashMap. But I like how Picasso will cache the Images for me and helps scale them etc.

public class HomeActivity extends FragmentActivity implements OnMapReadyCallback, LocationListener, GoogleMap.OnMapLongClickListener, DetailsDialog.DialogListener, PictureDialog.FinishedMemorySaving {

private GoogleMap mMap;
private LocationManager locationManager;
private Location location;
private String provider, title, desc;
private LatLng latlng;
private Memory memory;
private FragmentManager fm;
private HashMap<String, Memory> markers;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home);
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);

    markers = new HashMap<>();

    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    provider = locationManager.getBestProvider(new Criteria(), false);

    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        return;
    }

    location = locationManager.getLastKnownLocation(provider);

    locationManager.requestLocationUpdates(provider, 400, 1, this);

    if(location != null){
        Log.i("App Info", "Location found");
    } else {
        Log.i("App Info", "Location not found");
    }

}

//.....OTHER METHODS WORKING DELETED NOT NEEDED FOR THIS.....

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;

    mMap.setInfoWindowAdapter(new GoogleMap.InfoWindowAdapter() {
        @Override
        public View getInfoWindow(Marker marker) {
            return null;
        }

        @Override
        public View getInfoContents(Marker marker) {
            View view = getLayoutInflater().inflate(R.layout.marker_layout, null);

            Bitmap bit = null;

            ImageView markerImage = (ImageView)view.findViewById(R.id.markerImage);
            TextView markerTitle = (TextView)view.findViewById(R.id.markerTitle);
            TextView markerDate = (TextView)view.findViewById(R.id.markerDate);

            if(markers != null && markers.size() > 0){

    // ADDED THE CALLBACK ALONG WITH MARKER
                Picasso.with(getApplicationContext())
.load(markers.get(marker.getId()).getImageMem())
                        .centerInside()
                        .fit()
                        .into(markerImage, new MarkerCallback(marker));
                markerTitle.setText(markers.get(marker.getId()).getTitleMem());
                markerDate.setText(markers.get(marker.getId()).getFormatedDate());
            }

            return view;
        }
    });
}

public void setImages(String markerID, View view){
    Log.i("PATH TESTER 2", markers.get(markerID).getImageMem());

}

@Override
public void showMemory(Memory memory) {
    String markerID;
    Toast.makeText(getApplicationContext(), "The Minions have saved your Memory!", Toast.LENGTH_SHORT).show();

    markerID = mMap.addMarker(new MarkerOptions().title(memory.getTitleMem()).position(memory.getLocationMem())).getId();

    Log.i("PATH TESTER", memory.getImageMem());

    markers.put(markerID, memory);

    mMap.moveCamera(CameraUpdateFactory.newLatLng(memory.getLocationMem()));
}

public class MarkerCallback implements Callback {
    Marker marker=null;

    MarkerCallback(Marker marker) {
        this.marker=marker;
    }

    @Override
    public void onError() {
        Log.e(getClass().getSimpleName(), "Error loading thumbnail!");
    }

    @Override
    public void onSuccess() {
        if (marker != null && marker.isInfoWindowShown()) {
            marker.hideInfoWindow();
            marker.showInfoWindow();
        }
    }
}
}

Is there something I'm not doing right? The path is coming through fine and is correct. I've also set an ImageView in a dialog with the same path and it worked. Thanks for any help given.

EDIT:

I now seem to be getting the Error coming up that results in the MarkerCallBack when ever I click on the marker. It doesn't seem to set the actual Image on the marker though :/. Hope someone can help!