here are the instructions from the FAQ (located at top of page)
Can I post Images?
Images can indeed be shown in your posts. However, there is no facility at present for uploading images directly to this board. Therefore you must link to an image stored on a publicly accessible web server, e.g.
http://www.some-unknown-place.net/my-picture.gif. You cannot link to pictures stored on your own PC (unless it is a publicly accessible server) nor images stored behind authentication mechanisms, e.g. hotmail or yahoo mailboxes, password protected sites, etc. To display the image use either the BBCode [img] tag or appropriate HTML (if allowed).