public String postEventPhoto(String eventId, Media source, String message) throws FacebookException {
        ensureAuthorizationEnabled();
        HttpParameter[] httpParameters = new HttpParameter[] {source.asHttpParameter("source")};
        if (message != null) {
            httpParameters = HttpParameter.merge(httpParameters,
                                new HttpParameter[]{new HttpParameter("message", message)});
        }
        JSONObject json = post(buildEndpoint(eventId, "photos"), httpParameters).asJSONObject();
        return getRawString("id", json);
    }