Delete image after uploading to ftp server

I have a question about the times when deleting files after uploading them to an FTP server.

Let me explain, I have the following function, which uploads a file hosted on the mobile device to an FTP server and, when it finishes, calls a method that deletes it from the device.

Method that uploads image to FTP server

public void upLoadPicture() {

        try {

            FTPClient client2 = new FTPClient();
            client2.connect("192.168.0.26");
            client2.login("xxxx", "123");

            client2.setPassive(true);
            client2.setType(FTPClient.TYPE_BINARY);

            File dir = Environment.getExternalStorageDirectory();
            String filename = dir.getAbsolutePath()+"prueba.jpg";

            File f = new File(filename);

            client2.upload(f);
            client2.disconnect(true);

            //Llama al método para borrar la imagen del móvil
            Borra_imagen_dispositivo();

        } catch (Exception e) {

            Toast.makeText(this, "Error al conectar", Toast.LENGTH_SHORT).show();
            e.printStackTrace();

        }
    }

Method that erases the image after uploading it

private void Borra_imagen_dispositivo(){

        File dir = Environment.getExternalStorageDirectory();
        String filename = dir.getAbsolutePath()+"prueba.jpg";

        File file = new File(filename);
        file.delete();

    }

My question is, when it comes to images of a certain size, the upload usually takes a few seconds to complete, therefore, would there be a risk that the file will be deleted before it finished uploading the image? Should I sleep the call to the method Borra_imagen_device () for a while to make sure, for example using Thread.sleep or similar methods? Thanks