You can host the image on, say, imgur until you have enough posts to attach (though it looks better when posting hosted images with the [img] tags anyway). It's rational to keep a small post requirement for attaching images, or else some botnets can flood a forum with them.
It sounds like an exploiter, which means they'll be autobanned very soon. It could also be a desynch bug, though those do not tend to display negative quanta. During a desynch, pretty much anything can happen.