This is a little old by now, but I thought I’d share anyway.
The screen-capture below comes from “Breaker of Chains,” the third episode of Game of Thrones‘ fourth season (it aired on 4/20/2014). I noticed it right away, but haven’t had time to confirm and share it until now.
Apparently the CGI dragon effects from episode one ate into the budget for extras on the walls of Meereen.
They probably could have saved even more money by simply using a giant mirror.