You cannotNo, you can't post images in comments. You can, however, link to images as if they were a normal URL. Just use the normal [link text](url)
syntax.
Comments are meant to be lightweight, and primarily just text. Images in comments would be extremely ineffective given the potential image size that it would make the comment exchangecomments thread overly long, so it stands to reasonfor that reason keeping them linked as text would be functionally more useful.