put this code in your sig, but replace the { with [ and the } with ] and put the URL to the image you want {IMG}http://www.bris.ac.uk/Depts/Union/MotorClub/gallery/motorshow/TVR Tuscan (Silver)%202.jpg{/IMG}
[ I M G ]place_your_link_here[ / I M G ] LIKE THAT, BUT WITHOUT THE SPACES INBETWEEN THE BRACKET THINGS