Images are not stored in the cache

I have this method, everything is worked perfectly but images always got from server and not load from cache! what happened ?

public static void makeImageRequest(String Unique_ID, final View parentView, final int id) {

    String url = FILE_UPLOAD_FOLDER + Unique_ID + ".png";
    final int defaultImageResId = R.drawable.user;
    // Retrieves an image specified by the URL, displays it in the UI.  
    ImageCacheManager.getInstance().getImage(url, new ImageListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            ImageView imageView = (ImageView) parentView.findViewById(id);
            imageView.setImageResource(defaultImageResId);
        }

        @Override
        public void onResponse(ImageContainer response, boolean isImmediate) {
            if (response.getBitmap() != null) {
                ImageView imageView = (ImageView) parentView.findViewById(id);
                imageView.setImageBitmap(response.getBitmap());
            } else if (defaultImageResId != 0) {
                ImageView imageView = (ImageView) parentView.findViewById(id);
                imageView.setImageResource(defaultImageResId);
            }

        }
    });
}