Img src tag allowed in comments?

Hi, I was wondering if there was any way I could allow people to post images within comments without uploading them — a simple img src tag. I looked in the codex and I found the list of HTML you can choose to allow, and anything resembling img src wasn’t on there. Even still, I have them all allowed, but still nothing.

Any way I can allow this or just any HTML code known to man? Thanks.