--- a/slides02.tex	Tue Oct 02 14:42:51 2012 +0100
+++ b/slides02.tex	Thu Oct 04 13:01:55 2012 +0100
@@ -308,9 +308,9 @@
 \begin{frame}[c]
 
 \begin{center}
-\onslide<1->{\includegraphics[scale=0.5]{pics/stack1}\;\;}
-\onslide<2->{\includegraphics[scale=0.5]{pics/stack2}\;\;}
-\onslide<3->{\includegraphics[scale=0.5]{pics/stack3}\;\;}
+\only<1>{\includegraphics[scale=0.9]{pics/stack1}\;\;}
+\only<2>{\includegraphics[scale=0.9]{pics/stack2}\;\;}
+\only<3>{\includegraphics[scale=0.9]{pics/stack3}\;\;}
 \end{center}