for the very few that i understand from that page, you need to log in for see attachments, and you need to register for log in
if you want to post a pic from a forum that require registration, and want that all can view it, you need first to save the pic on your pc (right click, save image), and then attach the image here in the post (the button "manage attachments", in the new window in the section "Upload File from your Computer", browse your disk and select the pic you saved from the other place, then click upload and wait that the name appear near the "manage attachments" button .....always check with a preview, cause sometimes attachment uploads fails)