This is one of those excellent addons that once you've tried it, you'll wish that you had known about it earlier.

It currently works on most sites although not all, since some sites will simply refuse to send you the original jpeg/png (or the image may not even exist in that format on their servers). In those cases you can use the author's other addon "Save webP as PNG or JPEG (Converter)" to convert to jpeg/png.

It has never broken any website for me or caused me any trouble so it's pretty easy to forget that you even have it installed. But at the same it has made saving pictures so much less annoying.

How can I tell it's working if I forget I even have it? Well whenever a site forces a webp file on me then the "Save webP as..." addon makes a popup appear asking me if I want to convert the file. Since installing this addon, I see that popup much MUCH less often so on those rare occasions where I do see this popup, I suddenly remember this addon and realize that it's been silently doing its job in the background for a while.

Thank you for the great addon jscher2000!