While I personally think arguing over Devout versus White Mage is being picky, it's not necessary for what the character's wearing to be in the game for them to be wearing it. Otherwise that art of Paine with a Sephiroth dressphere would wind up being given a Dark Knight tag because that's the closest thing in-game to what she's wearing.
I am aware, but in this case there is a white mage outfit with ears in FFV, though it's worn by Krile not Lenna. Though I suppose there's no harm in tagging it with devout as well.
Regardless of the presence of the class in FF5, it's a Devout. Remember, artwork is not beholden to the game in any manner. Tag it cosplay if you're really anal.
