Hi Donna! Go to your profile page (here!). Click on User CP (right above your picture with your hubby). Look at the left side of the page and click on Edit Signature. You will see a box that says, "Edit Signature", then below that box there is a box that says, "Signature Picture". Just click "choose file" and you can grab a picture from your computer (can only be 500 size) and then click "save signature" and the picture will be in your signature like my roses - which are from my bush in the back yard!!!
Good luck!