Step 1: Select the highlighted rollover as shown
Step 2: Select the size as highlighted (medium 800 is best for quick display, esp on tablets/phones)
Step 3: Switch to BB Code as shown
And then copy the selection shown (the rest is not required for the image to display, and looks crap when posted).
Pasted and submitted, will result in the above image of your swan.
As you can see, there's the url with an img tag nested within - that's what gives the clickable image, which takes you to your Flickr page for it.
If you just wanted the image to show and nothing more, then select size first (no bigger than 1024), and instead of switching to BB code, look for the src="xxxxx.jpg".
Copy all within the "" marks, then paste inside img tags, like so....... xxxxx.jpg[ /img]....... with no space between the closing tag's [ and /
Or in the reply panel - select the image icon as shown, and paste in the pop-up that displays. Hit OK and you're done.
[img]http://thumbsnap.com/i/V5bjVzxe.png
That's all there is to it.