check your image.png in your project bundle or Assets.xcassets
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
guard !annotation.isKind(of: MKUserLocation.self) else {
return nil
}
let annotationIdentifier = "AnnotationIdentifier"
var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: annotationIdentifier)
if annotationView == nil {
annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: annotationIdentifier)
annotationView?.rightCalloutAccessoryView = UIButton(type: .detailDisclosure)
annotationView!.canShowCallout = true
}
else {
annotationView!.annotation = annotation
}
annotationView!.image = UIImage(named: "image.png")
return annotationView
}