Is there a way to specify which account is used for the picture of a person's tile?

[camaroz1985]

Is there a way to specify which account is used for the picture of a person's tile? (i.e. faceboock, twitter, etc.) I linked my wife's twitter to her account and now it displays that account as her picture, which she rarely updates. I wasn't sure if it was just whichever account was added last, or some other method.