I tried to do this earlier and I think I messed up, because it was directing off site instead of viewable in Lemmy. Does that mean I likely pasted the link instead of the image?
(if you're on mobile first select 'desktop site' from the browsers options or you'll get a low quality .webp version from the open image button. It'll work, but many ppl hate it)
Finally format it like this to embed it in a post/comment: