Adding images to posts in a Junkyard thread is no different than adding them to any post. It is only the first post of a Junkyard thread that has special formatting and editing rules. I just successfully added (and subsequently removed) an image to the post that you are referring to. Please try again as there must be something wrong with how the specific link is being processed (you could also try directly uploading the image from you computer as opposed to using the "from URL" option).
Re: Why Can't I Post Pictures in a Classifides Thread Reply?
I just posted the image 4 times and even added an image from your first post. If you upload the image from your local computer, there shouldn't be a link, the image just shows up. What browser are you using?
There is no question that the image system has been acting strangely for awhile now. It is one of the reasons why we are looking at migrating to the XenForo forum platform.