Norio has disabled attachments as it ended up using a huge amount of bandwidth and space for the site.
To post a pic, you need to open a photo account somewhere like www.photobucket.com (or any image hosting site), post the pics there, and then link to them using the image tag, something like this:
[img]http://photobucket.com/youraccount/picname.jpg/[/img]
Photobucket will also give you this code to copy and paste when you upload a pic there.