that gives you instructions on how to post a picture to a thread. Keep in mind you can't simply copy an image into your thread, it has to exist somewhere else on the web - in like a flickr account or sitting on your own webpage somewhere.
Mert: I don't know if this would work for your post, but using a site like photobucket.com makes it really easy. Under the thumbnail they have four choices -- the fourth one works really well on this site -- just copy and paste the "img" link. You could try adding
at the end, to see if that works. You can use the preview feature in the post to see if the photo shows up. Smaller image sizes (72 or 100 dpi) work best.