Since it doesn't have an extension on the end of it, sometimes vbulletin doesn't recognize it (ie, .jpg, .gif, etc)
Also, it's on a site that doesn't allow unregistered users/unlogged in users to view it.
My suggestion is to a) find a free site like http://www.photobucket.com to host it for you, then copy the location between img tags ([img][/img]) or b) email it to admin at strike3forums dot com & ask that it be uploaded to the server, then do the same with the [img] tags...