Your friend's avatar may appear in black and white as an error if a player's real avatar can't be displayed.

This may occur if your friend has uploaded their avatar from Facebook but your game account isn't linked to Facebook.

The error could also occur if you haven't updated the game and your friend is using an avatar which is only available in the latest updated version.

In rare cases, an avatar may appear in black and white because your friend's progress has been lost due to game errors.