That’s something which crossed my mind too.
Should it do that, maybe try to produce the replacement text as a link between [img] BBCode tags or markdown tags, if that’s possible. I guess it should and this may force the system to treat it as an image if it doesn’t do it on its own (unless it will display it as text). You indeed have to try it. Please post the results here 
FYI: Supported formatting in posts (markdown, BBCode, and HTML)
Markdown for images: Basic Syntax | Markdown Guide