I don't think that's a very clear explanation.
First off, the picture you want to use has to be online somewhere (i.e. not just on your computer's harddrive). If you don't know how to do this, ask.
You add the picture in exactly the same place that you add a text signature (yours is currently "Patience is a virtue"). Log in and go to Profile / Forum Profile Information -- the Signature box is near the bottom.
Suppose the URL of your picture is
http://tinyurl.com/gxgdz. Modify your Signature so it reads:
Patience is a virtue.[br]
[img]http://tinyurl.com/gxgdz[/img]This might look like goobledygook but it is simple really. Anything in square brackets is called a 'tag' and is an instruction to the forum.
[br] puts the picture on a new line, below the existing text. If instead you want the picture next to the text, remove the [br].
[img] and [/img] are the way you tell the forum where the picture is located. The location goes between the two tags.