NodeMCU provides nice file function which make it possible to store and read file to and from the internal file system.

Someone on Github provided a python script for down and uploading files. The problem was, that it had two flaws. The first thing is that it wants to take the whole file path as file name on the ESP. The other thing is that you have write the flag in the correct order...

So I started to write an own script. It is not finished yet, but the upload functionality already works.