Thinking this a little more.
what really are you trying to do.
Maybe the terms used are the issue.
If you are just looking for a way to post a image to any post and not a gallery forum.
If that is true, that would be called a inline image here.
Which can be done.
It is considered a attachment.
And you set the file size that it is displayed when viewing a post. If the file size exceeds the setting then it becomes a link.
