When a character looks really different from the card that just means the author of the card took the picture in a graphics mod/dhh setting instead of default vanilla, right?
Not necessarily - in creator you have the option to save tweaks for an existing card but "keep card"
After then you have to say "overwrite".
This means the appearance of the girl itself has changed but the picture of the card stay still the same.
Also you keep all achievements and stats of this character.
If you choose "Save New" you have to set a new appearance for the card (choose the scene, pose etc.), then girl on card and ingame will look the same.
But all existing stats of the character will be reset to zero.
If the card is assigned to a group you only have the option to "Save New" - to "Save (Keep Card)" you have to remove the card from the group before opening the creator.