4 images on a frame appearing each a a time - fine tuning beamer

I have a figure which consists of 4 plots, Full figure here, and I want to have them appearing one by-one in the presentation (from left to right, top to bottom). I managed to do this by including each plot separately using a combination of \subfloat and \pause:

\begin{frame} \frametitle{Cufflinks analysis - SRSF1}
\begin{figure}[t]
\centering
\captionsetup[subfloat]{labelformat=empty}
\subfloat[]{\label{} \includegraphics[scale = 0.20]{Image1.pdf}}
\pause \subfloat[]{\label{} \includegraphics[scale = 0.20]{Image2.pdf}}\\
\pause \subfloat[]{\label{} \includegraphics[scale = 0.20]{Image3.pdf}}
\pause \subfloat[]{\label{} \includegraphics[scale = 0.20]{Image4.pdf}}
\end{figure}
\end{frame}


 Result:

The issue with this solution is that the vertical spacing between the rows of images is rather large. I would like to reduced it in order to increase the size of each image - better use of space really.

If someone has a simple alternative where all 4 plots are part of a single image and each part is uncovered when needed it would be great.

Be gentle, this is my 1st beamer presentation.

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If the images aren't subject to change, you can probably achieve it by generating 4 big images corresponding to each step of the display : first with 1 image + 3 blank squares, second with 2 images + 2 blanks, etc. You can then use the \only<...> syntax to display them sequentially. –  T. Verron Sep 22 '12 at 11:52
Interesting. And how would I go about creating/overlaying the blank squares? –  fridaymeetssunday Sep 22 '12 at 12:08
You could use the image editor of your choice for that, but percusse's answer below is way more elegant and easy to set up. –  T. Verron Sep 22 '12 at 13:18
Splitting an image might be useful for you. –  kiss my armpit Sep 22 '12 at 19:24

It's not much different than what you have already.

\documentclass{beamer}
\usepackage{mwe} % For dummy images
\usepackage{lmodern} % To suppress some warnings

\begin{document}
\begin{frame}
\centering
\begin{tabular}{c@{}c}
\includegraphics[width=0.4\textwidth,trim=0 120 160 0,clip]{example-image-a}\pause%
&\includegraphics[width=0.4\textwidth,trim=160 120 0 0,clip]{example-image-a}\\[-1.5mm]\pause%
\includegraphics[width=0.4\textwidth,trim=0 0 160 120,clip]{example-image-a}\pause%
&\includegraphics[width=0.4\textwidth,trim=160 0 0 120,clip]{example-image-a}
\end{tabular}

\end{frame}
\end{document}


The trimming might not be good as I did it by eyeballing.

EDIT For the custom image, the following trim values seem to work.

\documentclass{beamer}
\usepackage{graphicx}
\usepackage{lmodern} % To suppress some warnings

\begin{document}
\begin{frame}
\centering
\begin{tabular}{c@{}c}
\includegraphics[width=0.3\textwidth,trim=0 270 260 0,clip]{SRSF1_details_1fig}\pause%
&\includegraphics[width=0.3\textwidth,trim=260 270 0 0,clip]{SRSF1_details_1fig}\\[-1.5mm]\pause%
\includegraphics[width=0.3\textwidth,trim=0 0 260 265,clip]{SRSF1_details_1fig}\pause%
&\includegraphics[width=0.3\textwidth,trim=260 0 0 265,clip]{SRSF1_details_1fig}
\end{tabular}

\end{frame}
\end{document}


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How did you find -1.5mm? –  Paul Gaborit Sep 22 '12 at 16:08
@PaulGaborit Just a quick guess. –  percusse Sep 22 '12 at 16:46
Thanks for the help @percusse, but it not really working for me. When I tested it I got superimposition of images in. Then I tried to check the trimming by trial and error using just one image: begin{frame} \frametitle{Cufflinks analysis - SRSF1} \centering \begin{tabular}{c@{}c} \includegraphics[scale = 0.48,trim=0 0 250 0,clip]{Image1.pdf} \end{tabular} \end{frame} . IN this case besides being clipped the image is also (bizarrely) relocated to the vertical centre. –  fridaymeetssunday Sep 23 '12 at 15:10
@krespim trim entries goes like left bottom right top. Right now you are only trimming the right side with 0 0 250 0. Can you upload you image to the question so that I can modify my answer? –  percusse Sep 23 '12 at 15:16
@peruse: done. I've added the link to the figure (pdf) –  fridaymeetssunday Sep 23 '12 at 15:47

You could use TikZ and put the pictures in nodes. With no inner sep or outer sep they align perfectly. If you need spacing, you can use <position>=<distance>, like above right=3mm

Code

\documentclass{beamer}
\usepackage{tikz}

\begin{document}

\begin{figure}[t]
\begin{center}
\begin{tikzpicture}
\node[above right,inner sep=0,outer sep=0] {\includegraphics[scale=0.7]{test}};\pause
\node[above left,inner sep=0,outer sep=0] {\includegraphics[scale=0.65]{test}};\pause
\node[below right,inner sep=0,outer sep=0] {\includegraphics[scale=0.75]{test}};\pause
\node[below left=0.5cm,inner sep=0,outer sep=0] {\includegraphics[scale=0.6]{test}};
\end{tikzpicture}
\end{center}
\end{figure}
\end{frame}

\end{document}


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