I've tried these extensions: Don't Accept Image/Webp Image Forcer Webp/Avif converter Save webP as PNG or JPEG (Converter) They no longer work. Now, Firefox is determined to save images as webp. Researching this problem has turned up a bunch of people saying it's not Firefox doing it, but Opera does not do this. I have always done my work on Firefox and am wondering if there's any way to prevent this or if I just need to transfer all my work over to Opera and be done with Firefox.