I imagine that’s due to the specific host. Many sites will have an image link that actually diverts to a page - for example, imgur generally does this - but if you dig in you can sometimes extract the direct image link. You need this direct link to get it to work.
On imgur, you can get it after you upload by clicking “Get share links” and using the URL from the BB code.
You should use the direct image link in the URL box, that will allow the image to open in the normal way, rather than appearing in the body.
Didn’t work
I imagine that’s due to the specific host. Many sites will have an image link that actually diverts to a page - for example, imgur generally does this - but if you dig in you can sometimes extract the direct image link. You need this direct link to get it to work.
On imgur, you can get it after you upload by clicking “Get share links” and using the URL from the BB code.