In Game of Thrones season 5 episode 3, "High Sparrow," we see:
Tyrion and Varys, on their way to see Daenerys Targaryen, stop by a brothel in Volantis where Tyrion is kidnapped by Jorah Mormont. How did Jorah know this was Tyrion Lannister and not some random dwarf? Jorah fled Westeros decades ago, so there is no way he would know what Tyrion would look like.