public class PhotosAdapter extends RecyclerView.Adapter<PhotosAdapter.PhotosViewHolder> {

    private Context context;

    private List<Photo> items;

    public PhotosAdapter(Context context, List<Photo> items) {
        this.context = context;
        this.items = items;
    }

    //other code here

    public void addAll(List<Photo> newItems) {
        int beforeSize = items.size()-1;
        items.addAll(newItems);
        notifyItemRangeInserted(beforeSize, newItems.size());
    }

}

new PhotosAdapter(getContext(), new ArrayList<Photo>());

new PhotosAdapter(getContext(), new LinkedList<Photo>());

adapter.addAll(myPhotos);