Portrait of the Royal Family of Arendelle, drawn for the sequence “For the First Time in Forever”. You can see it hanging on the wall on the top left corner, when Anna enters the portrait gallery in the movie.
GUYS. The mom’s hair color is supposed very dark brown, even darker than the King’s. So why does this Queen have blonde hair? My theory is this: Elsa and Anna’s real mom died and the king remarried to the current Queen. That would explain why Anna’s hair is a medium between the King’s hair color and the blonde’s, instead of a dark brown, like the king’s and current queen’s.
Or… maybe the animators kinda got lazy and just wanted to put that piece of concept art in there for the heck of it.
I wouldn’t call that lazy necessarily, just kind of an Easter egg, like Rapunzel’s cameo in the movie.
But that theory is sort of debunked by the fact that Elsa and her mother are nearly identical.