I NEED HELP!!!!!

CAN SOMEONE PLEASE HELP ME! I WANT TO KNOW HOW YOU CAN ADD A SIGNATURE OF A SAVED PICTURE OR SOME OTHER PICTURE BESIDES THE ONES WITH THE HTML! THE ONLY ONES I CAN ADD ARE THE GOOGLE ONES I CAN'T EVEN ADD THE YAHOO GROUP ONES! CAN SOMEONE PLEASE EXPLAIN IN DETAIL OR YOU CAN ALSO PM ME! THANKS BUNCHES!!!!!!!!