It is wonderful to automate boring stuffs with Python. In Japan, new introductory books are being published every month and more and more Pythonistas are working on automation. A Python script that is useful to you may be useful to others. So I talk about how to enable others to use your script. In this talk, I use a simple script which can reduce the width and the height of a specified image in your computer. I assume someone who's read the introductory book can understand the script. First, I introduce Command Line Interface (CLI) to solve hardcoding in the sample script. After implementing CLI, you don't need to edit the script. Second, I introduce Grafical User Interface (GUI) to make the script more user-friendly. Finally, I introduce web application so that users can the script without installation. All users have to do is connecting the Internet! The timeline is supposed to be the following: # Introduction (3min) - self-introduction - motivation of this talk - sample script (pathlib, Pillow) # CLI (5min) - problem: need to edit the script - introduce argparse module (pass target file path from command line) - about positional arguments and optional arguments - check whether a path points an existing file (type parameter of add_argument()) # GUI (9min) - problem: CLI is not easy to handle than GUI - introduce eel - eel's elements: HTML, CSS, JavaScript - hello world in eel - file access in eel app - convert sample script to eel app (user can see which image is specified as target