Note: This is in a very early stage of development and not actually meant to be used productively but to learn a thing or two about (custom) file formats and compression.
The reference implementation uses tkinter and py-lz4framed.
Customize (optional) and run create_sample.py, which will create a .cif file you can display using display.py.
As said in the specification, an alpha channel may be implemented. Also, the reference implementation does not check the image width, height or comment size, which never is a good idea and the generated sample image could probably be improved.