User blog comment:Deathwalker 13000/The Villains Multiverse Portrait Project/@comment-25008763-20150731130424

I agree with Misery below.. order them by general prominence (as in the "Big Goods" and the "Big Bads")

There's a means to signify alter-egoes and even status but it may be too much work, considering this is an ambitious project as is.. basically it'd go like so:

a portrait of an alter-ego has an "ALT" symbol on the side, the portrait of a deceased character has a little skull on the side. (alternatively each portrait has a star (gold for "core" characters, silver for "prominent" and bronze for "supporting cast" - the skull woud still be used for deceased characters)