>>214033581
For .webp files I have this extension for firefox:

https://github.com/jscher2000/Save-webP-as-extension

Handily, whenever you open a .webp file it will generate this overlay that notifies you it's a webp and provides buttons so you can save it as a normal file.

However it will only do this if you open the image in its own tab, like it won't do it if the file is embedded in a news article. So you need to get into the habit of copying files' location and opening in a new tab prior to saving. If you hail mary it and save from the article then you're risking downloading an unconverted .webp.

The same developer also has another extension that appears to encourage websites to serve up a JPG/PNG instead of .webp files but I haven't installed that one as I've only just seen it (so I dunno how well that works):

https://github.com/jscher2000/dont-accept-webp