Yea it’s one or the other, so that it federates nicely
What I do is link the URL in the main post (to get a thumbnail, and because that’s what people expect), and the image in the post body. You can insert it like this
![alt text](image URL)
Ah I see it’s just Lemmy failing to get the thumbnail that I was trying to fix. I guess it’s just something in Lemmy’s code.
Oh that is odd, and it might be related to your instance because the thumbnail is showing up on lemmy.ca
Here is the post on each instance: