External url for featured images, cover images and logo image... etc

I set up my personal blog using Ghost three years ago, back then it was v0.11. I’m working on upgrading to v3 now. I found that the options to enter external image url for featured images and images in settings like cover photo and logo are gone. Am I missing them or are they just not allowed in v3? They were all allowed in v0.11 and were easy to find.