Go to the thumbnail picture that you want to post.
Click on it.
It will open into a larger picture.
When you click to enlarge on the photo that you want to display look on the right and it shows some different options for posting.
Look at the last one that says,"IMG Code" and copy and paste that to your post on this bulletin board, without using the image icon to insert the image, since it already has the image commands added.
move your cursor to the end of the last bracket to continue your post. You want nothing other than the URL that you copied from the photograph inside the brackets.
Finish what you are typing and click on Preview to see if it worked.
If it did, click on Post.
If not, Beat on the computer in frustration, my favorite tool to do this is a 28 oz framing hammer.