Compare colliding objects

Simple question. How do I compare the size of two objects when they've collided and do something only if one is larger than the other?

give the sprite object an instance variable called coliddedUID

Sprite On collision with other object

->pick nearest (enemy)

-sub event->system compare 2 values

sprite.imagewidth*sprite.imageheight <= enemy.imagewidth*enemy.imageheight

-> do whatever ever action should happen if the sprite is smaller than the enemy it hit