Hi @escaflowne,
Thank you for your message. I am sorry you have encountered a problem with our plugin. Do not worry, I will try to explain you everything below.
I ran a test on your website. I simulated browsers with and without WebP support to make sure everything was working. Thanks to this, I can check how much your original images weigh (i.e. what was before installing our plugin) and how much the images converted by our plugin weigh.
Here are the results of my tests:
This means that the plugin is working properly and all images are displayed in the version converted by the plugin.
Below I have attached the instructions:
If you encounter any other questions, please, feel free to reach out to me.
I wish you a great day,
Mateusz