A way to disable preview images.

Aye. Specifically, in the context of, I want to have text that links to an image or video, without the text being replaced by a thumbnail.

I really hope this is seen by a Rioter, because it does the same with entire documents. I just had something embed when I only wanted to post a link. I love embedding, don't get me wrong, but disabling preview would be a great feature.