Well they are all from the cat family they kinda have the same shape of the face as well but the pattens are not alike at all!
What Are The Similarities Between A Leopard, Lion, And Tiger?
They have similarities and differences being sub species of the genus panthera and are all 'big cats'. Panther refers to a larger family and not a type ( jaguar's may be referred to as 'panther') of big cat.
animals.about.com
animals.about.com