search for an image in google.........unless you have sumone to host an image of your own............copy the http addy at the top.........
go in to user cp and select edit signature.......
u see the box where you normally type in to..........just above is a yellowish icon which looks like a mountain....click on that.......you should then see a box pop up.........paste the http addy into it.........!
once you have done that preview siggy and if ur happy save it! :$
clear as mud eh!!!!