public void setTextureFormat(Texture.Format format) {
        if (format == Texture.Format.RGB565) {
            mConfig = Bitmap.Config.RGB_565;
        }
        else {
            mConfig = Bitmap.Config.ARGB_8888;
        }
    }
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