public void getImageAsync(ReadableMap map, ImageDownloadListener listener) {
        if (listener == null) {
            ViroLog.warn(TAG, "The given ImageDownloadListener is null. Doing nothing.");
            return;
        }

        if (!map.hasKey(URI_KEY)) {
            throw new IllegalArgumentException("Unable to find \"uri\" key in given source map.");
        }

        getImage(Helper.parseUri(map.getString(URI_KEY), mContext), null, listener);
    }
This method fetches an image asynchrously

@param map a ReadableMap with a "uri" key, ideally the same one we get from the JS layer
@param listener object that will be called once the image is fetched.
android/viro_bridge/src/main/java/com/viromedia/bridge/utility/ImageDownloader.java