I wasn't too sure whether to put this as a bug or suggestion, but in the end I decided it's a bug as a webp is defined as an image format.
When attempting to upload an image to an episode via URL, it will fail if it's in webp format.
What I'd currently have to do instead is save the picture, convert it, go to the episode --> gallery, upload from file, go to next episode and continue (seeing as the batch uploader only allows by URL).
