why does kim kardashian look bigger than megan fox if they are both same size?

Why does kim kardashian look bigger than megan fox if they are both same size?

when i see pictures of kim kardashian always looking gorgeous of course not to be a hater because dont get me wrong she has an awesome body but why does she look small sometimes then really big? and can you look bigger sometimes with different bra or no bra and that be the case here?they say that megan fox is a size 34c then why does she look so small compared to kim if shes the same size?she also has more cleavage than megan