Graphic Jumps Up in Beamer

Question

Consider the following code:

\begin{frame}{title}
    \hfill\includegraphics[width=7cm]{1.pdf}\hfill\hfill

    \vspace{2cm}

     \hfill\includegraphics[width=7cm]{2.pdf}\hfill\hfill
\end{frame}

This creates two slides: 1.pdf is shown on both, while 2.pdf is only shown on the second one. The problem is that when you move from the first slide to the second, 1.pdf jumps a little up, as if it is making room for 2.pdf (although there are plenty of room left for it!)

Here's a demonstration:

You can get the source + PDF from here, and see it for yourself. (It is best to view the PDF in the full-screen mode.)

I tried absolute positioning of 1.pdf, using textpos (and a bunch of other techniques). However, this seems to be an overkill, and, moreover, placing the graphic at the center of the page (horizontally) seems hard.

Any suggestions?

Answer 1

Use the \visible<2>{...} macro to make the second image reserve space on the first slide to achieve correct alignment, but only be visible on the second slide. For text you can also use \uncover<2>{...} to achieve a semi-transparent effect (if configured), but it doesn't seem to have an effect on included images.

\documentclass[serif,xcolor=dvipsnames]{beamer}

\mode<presentation>
{
  \usetheme{Warsaw}
  \usecolortheme{default}
  \setbeamercovered{transparent}
  \setbeamertemplate{footline}[frame number]
}

\begin{document}

\begin{frame}[plain]
    \begin{center}
      \includegraphics[scale=.3]{1.png}

      \vspace{2cm}

      \visible<2>{\includegraphics[scale=.3]{2.png}}
    \end{center}
\end{frame}

\end{document}

Answer 2

I cannot see it. However, if you want to center the images use the environment center

\PassOptionsToPackage{demo}{graphicx}
\documentclass{beamer}

\begin{document}

\begin{frame}{Title}
\begin{overprint}
  \begin{center}
      \includegraphics[height=2cm]{1}

      \vspace{2cm}
      \onslide<2>{\includegraphics[height=2cm]{2}}
     \end{center}
  \end{overprint}
\end{frame}

\end{document}