Uploading this keeps giving me error for some reason

Hey there, so I've been wanting to upload this artwork of Napoleon I found on bbs and here's the link. I really like it but whenever I download it my laptop says "looks like we don't support this format" when it's just JPG? To not mention the error here as well.. Can someone with experience help me extract the artwork somehow if it's possible?

http://img.nga.178.com/attachments/mon_201812/20/-7Q5-fci8Ze.jpg.medium.jpg

It’s a WEBP image, not a JPEG. The file extension in the URL is misleading.

kittey said:

It’s a WEBP image, not a JPEG. The file extension in the URL is misleading.

What even is that format? Okay I used an online converter and it seems to have worked.. Thanks!