file 1: Image51315.jpg
file 2: Image59192.jpg
...

Drive.DriveApi.requestSync(mGoogleApiClient).await();
        Drive.DriveApi.getRootFolder(mGoogleApiClient)
                .listChildren(mGoogleApiClient)
                .setResultCallback(new ResultCallback<DriveApi.MetadataBufferResult>() {
                    @Override
                    public void onResult(DriveApi.MetadataBufferResult result) {
                        if (!result.getStatus().isSuccess()) {
                            Log.v("DKDK", "Request failed");
                            return;
                        }
                        MetadataBuffer metadataBuffer = result.getMetadataBuffer();


                        //Log.e("Resultados",""+metadataBuffer);
                        Iterator itr = result.getMetadataBuffer().iterator();
                        while (itr.hasNext()) {
                            Metadata metadata = (Metadata) itr.next();
                            mImageName = metadata.getTitle();
                            Log.e("GDRIVE", "Title " + metadata.getTitle() + " MimeType " + metadata.getMimeType());
                            FileID = metadata.getDriveId();
                            Log.e("GDRIVE", "" + FileID);
                        }
                        if (metadataBuffer.getCount() == 0) {
                            Log.e("GDRIVE", "Creando archivo nuevo");
                        } else {
                            // FileID = metadataBuffer.get(0).getDriveId();
                            Log.e("GDRIVE", "Hay Archivos");

                        }
                        metadataBuffer.release();
                    }
                });

private void storeImage(Bitmap image) {
        File pictureFile = getOutputMediaFile();
        if (pictureFile == null) {
            Log.e("FOTO",
                    "Error creating media file, check storage permissions: ");// e.getMessage());
            return;
        }
        try {
            FileOutputStream fos = new FileOutputStream(pictureFile);
            image = Bitmap.createScaledBitmap(image, 500, 500, false);
            image.compress(Bitmap.CompressFormat.PNG, 100, fos);
            fos.close();
        } catch (FileNotFoundException e) {
            Log.d("FOTO", "File not found: " + e.getMessage());
        } catch (IOException e) {
            Log.d("FOTO", "Error accessing file: " + e.getMessage());
        }
        Log.e("FOTO", "PATH>> " + mCurrentPhotoPath);
    }

    /**
     * Create a File for saving an image or video
     */
    private File getOutputMediaFile() {
        // To be safe, you should check that the SDCard is mounted
        // using Environment.getExternalStorageState() before doing this.
        final File mediaStorageDir = new File(Environment.getExternalStorageDirectory()
                + "/Android/data/"
                + getApplicationContext().getPackageName()
                + "/Files");

        // This location works best if you want the created images to be shared
        // between applications and persist after your app has been uninstalled.
        // Create the storage directory if it does not exist
        if (!mediaStorageDir.exists()) {
            if (!mediaStorageDir.mkdirs()) {
                return null;
            }
        }


        Log.e("AFUERAIV", "" + mImageName);
        mCurrentPhotoPath = (mediaStorageDir.getPath() + File.separator + mImageName);
        mediaFile = new File(mediaStorageDir.getPath() + File.separator + mImageName);
        return mediaFile;
    }