OP -- Ok, I see you already saw that the link didn't work ...
If you'd like to try again, here are a couple of options:
Option One (Less elegant) -- At the bottom of the edit box (the box you type a response in) you will see three buttons. click on the one to the far right that says "Use Full Editor"
Once that window opens, under the word "Post" you will see another box to type a response in. Across the top of it, you'll see a number of little icons. The 14th one from the right looks like the planet Earth with a chain link.
click on it.
In the first box, type (or paste) the actual address to the photo (what you tried to do above but couldn't because we don't really like that web site, but you should be able to type the address to it in this box)
the second box will be for you to type what ever title you want to give the image.
Then, it will kick you back to the "Post" box to finish writing your post.
When finished, you just go all the way to the bottom and click "Post Reply"
Option Two (more elegant and preferred) -- Easier, though, would just be to click on the link (below the edit box) that says "Attachment Manager" which will allow you to post an image directly to your post without making us all go to that overly political, free-speech hating social media site

We have directions on image attaching in the column on your left.
Thanks,
John