Two characters that look, are dressed, stand mirrorically identical to each other.

Despite the name, the tag doesn't refer to literal [[twins]], but the mere visual similarity between two characters.

If characters are actual [[twins]] add also appropriate tag. Same if both characters are actually [[dual persona]] of same character.

If picture simply contains just one character twice in mirrorically [b]identical[/b] pose, then use [[symmetry]] tag.
mirror twins