While I personally agree, I'm not so sure that's a good tip because "use the embedd code" was what got me into alike trouble more than once.
Meanwhile, I simply right-click the image I want to post and copy the image url to post that into my comment. Spares me stripping markup from the embed codes and also spares me spam accusations resulting out of using the "Image Link".
At least, that's what I ended up doing to satisfy the crowd.