chrome keeps changing downloaded images to webP which is annoyin af. can't even find a way to disable it
https://chrome.google.com/webstore/detail/save-image-as-type...
In theory, you could probably do some combination of altering the user agent, and/or blocking .onload for webp images (which is often used to detect webp support).
If you changed both, most sites would probably serve you a jpg/png version.