Image capabilities are still possible as all you'll need to do is encode media in to base32 and then spew that to brother channel, #hn-images or something.

IRC is perfect for long blinding data dumps.

If the user opts in to imagery, let the client connect to that channel. Sure you'll loose out on the image if you were not available but irc is like that anyway.

Having your client throw [image:~hackernews_logo] to indicate that you've posted an image is no less spam than someone announcing that they've changed their nick to "doublerabbit|Zzz".