Beamer with itemize and images in item: avoid jumps

Question

I am preparing a Beamer presentation.

In one frame I have a bulletpoints list (itemize).

I would like to show some small images (logo) in each item of the itemize, together with the text.

I have two situations, neither of which is ideal.

In the first case, I have:

\documentclass{beamer}
\begin{document}
\begin{frame}{Introduction}
\centering
{  \textbf{Quantum Information Processing}}

\begin{itemize}[<+->] 
    
    \item \includegraphics<1->[width=0.9cm]{example-image-duck} University of Oxford  
    \item \includegraphics<2->[width=2.5cm]{example-image-duck} Université de Montréal
    \item \includegraphics<3->[width=2cm]{example-image-duck} Université du Quebec 
    
\end{itemize}
\end{frame}
\end{document}

The problem with this code is that the images in the later items do not "take space" when they are not shown, so in the second overlay the position of the first item "jumps", with respect to the first overlay, and so on.

On the other hand, if I have:

\documentclass{beamer}
\begin{document}
\begin{frame}{Introduction}
\centering
{  \textbf{Quantum Information Processing}}

\begin{itemize}[<+->] 
    
    \item \includegraphics[width=0.9cm]{example-image-duck} University of Oxford  
    \item \includegraphics[width=2.5cm]{example-image-duck} Université de Montréal
    \item \includegraphics[width=2cm]{example-image-duck} Université du Quebec 
    
\end{itemize}
\end{frame}
\end{document}

the later images are shown in all the overlays, also when the "items" they are in are not shown.

I have seen similar questions here, such as this, but their situations and requirements are slightly different.

Thanks in advance for any help!

Answer 1

While I prefer my frames to be all top aligned (it's also available as a class option), with

\setbeamercovered{transparent=5}

your graphics don't ovserve that setting while they are “covered”.

The manual states in section 17.6 Transparency Effects

Ideally, there would be an option to make covered text “transparent.” […] Unfortunately, pgf does not support real transparency yet. Instead, transparency is created by mixing the color of the object you want to show with the current background color (the color bg, which has hopefully been setup such that it is the average color of the background on which the object should be placed). To install this effect, you can use:

 \setbeamercovered{transparent}

[…] The transparency effect will automatically apply to all colors, except for the colors in images. For images there is a workaround, see the documentation of the pgf package.

(PGF handles the vector graphics side of Beamer (not \includegraphics, though.))

This means that you need to have transparent versions of your images named in a very specific format available. See also the documentation of the xxcolor package.

That would be too much work for me (especially a day before the deadline).

---

If you will be okay with no transparency on this frame you could just use

\setbeamercovered{invisible}

which is the default or you can use

\begin{itemize}[<visible@+->]
   % …
\end{itemize}

which doesn't use the default \uncover way of handling the overlays but the \visible one.

Code

\documentclass{beamer}
\setbeamercovered{transparent=5}
\usepackage[export]{adjustbox}
\begin{document}
\begin{frame}{Introduction}
             %{Quantum Information Processing} % subtitle?
{\centering % \centering doesn't take an argument
 \textbf{Quantum Information Processing}\par}

\begin{itemize}[<visible@+->]
\item \includegraphics[width=0.9cm, valign=c]{example-image-a}
      University of Oxford
\item \includegraphics[width=2.5cm, valign=c]{example-image-b}
      Université de Montréal
\item \includegraphics[width=2cm,   valign=c]{example-image-c}
      Université du Quebec
\end{itemize}
\end{frame}
\end{document}

Answer 2

The easiest way to avoid jumping is to use a top aligned frame:

\documentclass{beamer}

\usepackage[export]{adjustbox}
\begin{document}
    
\begin{frame}[t]
\frametitle{Introduction}
\centering
{  \textbf{Quantum Information Processing}}

\begin{itemize}[<+->] 
    
    \item \includegraphics<1->[width=0.9cm,valign=c]{example-image-duck} University of Oxford  
    \item \includegraphics<2->[width=2.5cm,valign=c]{example-image-duck} Université de Montréal
    \item \includegraphics<3->[width=2cm,valign=c]{example-image-duck} Université du Quebec 
    
\end{itemize}
\end{frame}
    
\end{document}