Close. First the image you used was the thumbnail not the large version. Click on the thumbnail to get the bigger version.
Then copy the image location and paste into a post. Remove the "?number" following the .jpg.
Lastly, enclose the image URL in [ img ] ... [ /img ] tags. One trick, this works well (at least for me): highlight the text, then click the "Img" button above. Then it adds both tags for you.
Oh and ya'. I'm sorry but I don't know what the coral is. It doesn't look like an elegance though.