The following is from the forum FAQ link:
Why can’t I add attachments?
Attachment permissions are granted on a per forum, per group, or per user basis. The board administrator may not have allowed attachments to be added for the specific forum you are posting in, or perhaps only certain groups can post attachments. Contact the board administrator if you are unsure about why you are unable to add attachments.
Can I post images?
Yes, images can be shown in your posts. If the administrator has allowed attachments, you may be able to upload the image to the board. Otherwise, you must link to an image stored on a publicly accessible web server, e.g. http://www.example.com/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 the BBCode tag.
Looks like you need to get permission from R. Szego.