RE: how do you......
Click the HELP button in the row of icons at the top of this message (near it anyways) and you will get a list of "how to" items.
Basically you list a link to where your picture is stored -- in the signature box on the settings page (notice the icon called SETTINGS in the same row of icons).
If you are still confused ask again - someone can step you through it.
Personally, I'm still trying to find out how some folks have two links using a headline. I can do one - but I can't seem to get two different ones.