John Muller talks about images and hosting.

It doesn’t matter how you host the images, there’s no SEO-bonus for having them on the same host/domain. However, since changing image URLs is “hard”, I’d use your own hostname for the CDN (avoid https://t.co/Y1ND46l9ij and use https://t.co/fWMc6CFPZ0), so you can change CDNs.

— 🍌 John 🍌 (@JohnMu) March 5, 2019

Transcript:

“It doesn’t matter how you host the images, there’s no SEO-bonus for having them on the same host/domain. However, since changing image URLs is “hard”, I’d use your own hostname for the CDN (avoid yoursite.cdncorp.com  and use http://cdn.yoursite.com ), so you can change CDNs”