These directions were posted on May '13. They worked for me, so hopefully you all will find success, as well.
In the upper right hand corner are four icons (a globe, something else, a star and a person)... click the person.
Under your avatar, there is a link that says "signature settings".
BEFORE YOU START TYPING STUFF IN THE BOX: click the < > icon (show source).
Then insert your html code.
Then click the show source button again.
You should be able to see the pictures... not code.
It worked for me, hopefully you guys can get it to work for you as well.