Why is the sidebar image 1080p?

The sidebar image on the homepage, https://lemmy.world/pictrs/image/913f672f-5d9a-48b5-af28-1a8fbb4f7bc7.jpeg?format=webp, is a 1MB 1080p jpeg that gets loaded every time I open the homepage (at least without caching).

Wouldn't it improve both bandwidth use and page load speeds to rescale that image to the smaller size it is actually rendered at?