General Discussion

I copied the image from imgur and it was a webp.

Here's the phone procedure (No kidding)

Save the image to the camera roll.

Either by opening the photo or holding your finger down, share -- SAVE TO FILES

Go to the files app. Find the photo.

Hold your finger down (do not click) and select quick actions --- convert image
Convert to jpeg.
Saves a jpeg copy.

With that copy, open and share -- save (goes to camera roll) You can also hold finger down and share -- save

Go back to the camera roll, there it is.

Upload and share.

I probably have an app that converts images, but can't recommend that to anyone, who might not have the app.
Apple, you are bonkers at times.

On the computer, just right-click or control-click and select quick actions -- convert.

(or use preview app, export as ... )

I do spend a bunch of time with GIMP, creating those FAFOS and F U's.