\begin{frame}{Mercurial Contributors}
  From \url{http://ohloh.net/p/mercurial/map}:
  \begin{center}
    \begin{tikzpicture}
      \node (map) {\includegraphics[height=7cm]{contributors}};
      \tikzstyle{every node}=[font=\Huge\bfseries]
      \node<2>[black, shift={(0.8pt, -0.8pt)}] {Thank you!};
      \node<2>[orange!50!red] {Thank you!};
    \end{tikzpicture}
  \end{center}
\end{frame}