At some point, playing cards graduated from having wildly varying designs to having a standard design. Kings of Hearts are now "suicide kings," because of the sword behind their head, and Jacks of Spades and Hearts are "one eyed jacks."
The only way to get those nicknames is standardized imagery. Well, not standardized exactly, designs will still vary, there's still a lot of art to card design--just google image search for "King of Hearts" to see the variety, but certain common features like the pose will remain fixed across many decks.
So how and when did card faces essentially turn into heraldry?
What determined why some of them were drawn in profile (one-eyed) rather than portrait?