You should have clicked on the picture, it would take you to the webpage that the picture is part of.
Then go down the page to the picture you wanted. It's clickable so do that.
That will give you a page only with that picture and slightly enlarged. At that page select and copy the URL.
Then at the bottom of the message box here click the image link and post the copied URL. Remove the s from https to make it http. Then click on preview and there you go.
But it's not always that simple