First the need to save the picture to your computer. Then you need to upload it onto something like photobucket - thats what i use.(
www.photobucket.com) You do this by going onto your photobucket account and were it says 'browse' clicking on that photo. Then you click on 'Upload' Wait a while. When the picture has uploaded, you have to click on the box next to the picture. Then you scroll down and click on 'Generate codes' when that page comes up, copy and paste the IMG code into the signiture box. Then save your changes. I hope that helps!