This is a MWE of my code:
\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows}
\mode<presentation> {
\usetheme{Frankfurt}
\usecolortheme{dolphin}
}
\begin{document}
\begin{frame}
\begin{columns}[c]
\column{.7\textwidth}
\only<1>{
\begin{tikzpicture}
\node[anchor=south west,inner sep=0] at (0,0) {\includegraphics[width=0.9\textwidth]{fig.png}};
\end{tikzpicture}
}
\only<2>{
\begin{tikzpicture}
\node[anchor=south west,inner sep=0] at (0,0) {\includegraphics[width=0.9\textwidth]{fig.png}};
\draw[green,thick,rounded corners] (4.8,5.2) ellipse (0.28 and 1.5);
\draw[->, line width=2pt, -triangle 60] (6.3,5.2) -- (5.2,5.2);
\end{tikzpicture}
}
\only<3>{
\begin{tikzpicture}
\node[anchor=south west,inner sep=0] at (0,0) {\includegraphics[width=0.9\textwidth]{fig.png}};
\draw[green,thick,rounded corners] (5.8,3) ellipse (0.28 and 1.5);
\draw[->, line width=2pt, -triangle 60] (7.1,3) -- (6.1,3);
\end{tikzpicture}
}
\column{.35\textwidth}
\vspace{-1.cm}
\setbeamercolor{normal text}{fg=gray,bg=}
\setbeamercolor{alerted text}{fg=black,bg=}
\usebeamercolor{normal text}
\begin{itemize}
\item \alert<+>{Some text goes here sdsdf sdfsdfsdfsdf.}\\[4ex]
\item \alert<+>{Some more text here sdfdsf.}\\[4ex]
\item \alert<+>{And some text here.}
\end{itemize}
\end{columns}
\end{frame}
\end{document}
This creates three slides with the same image:

It might not be noticeable when seen separate but the grey square does not maintain a fixed position within the slides. How do I get it to stop moving around?
Here's the grey square I use: 
overlayareaenvironment and it worked. Want to make that into an answer so I can mark it as accepted? – Gabriel Mar 12 '13 at 13:35