# Remove padding in table with images

I have a table with 2 small images in each cell. I reduced the horisontal padding with

\setlength{\tabcolsep}{0pt}

But I still have a white vertical space between a table separation line and images (beneath the image). All tipps that I found are about making the space bigger.

But how can I remove that vertical padding?

How can I remove the horizontal space between the images?

\begin{table*}[t]
\begin{center}
\caption{Comparison of the form and position}
\setlength{\tabcolsep}{0pt}
\begin{tabular}{|c|}
\hline
\multicolumn{7}{|c|}{-2.5 cm}
\\ \hline
\includegraphics[height=27mm]{image1.png}
\includegraphics[height=27mm]{image2.png} \\ \hline
$\varphi$=0.5, 126 m/s \\ \hline
\end{tabular}
\end{center}
\end{table*}
-
Try changing \tabcolsep to -\arrayrulewidth? Or no vertical rules. –  Bernard Aug 8 '14 at 10:14

The interrow padding is because the bottom of an image is on the baseline and the tabular rows take into account the possible depth of descenders.

We can remove the white space by lowering the images on the top row. A similar trick can be used to have a symmetric padding above the images.

\documentclass{article}
\usepackage{graphicx}
\usepackage{siunitx}
\sisetup{per-mode=symbol}
\begin{document}
\begin{center}
\begin{tabular}{@{}c@{}}
\hline
\\[-\ht\strutbox]
\includegraphics[height=27mm,raise=-\dp\strutbox]{example-image-a}
\includegraphics[height=27mm,raise=-\dp\strutbox]{example-image-b} \\
\includegraphics[height=27mm]{example-image-a}
\includegraphics[height=27mm]{example-image-b} \\ \hline
$\varphi=0.5, \SI{126}{\meter\per\second}$ \\ \hline
\end{tabular}
\end{center}
\end{document}

-

You can change the \arraystretch like

\def\arraystretch{0.15}

Choose an appropriate value.

\documentclass{article}
\usepackage{graphicx}
\usepackage{siunitx}
\sisetup{per-mode=symbol}
\begin{document}
\begin{center}
\setlength{\tabcolsep}{0pt}
\def\arraystretch{0.15}
\begin{tabular}{c}
\hline
\includegraphics[height=27mm]{example-image-a}
\includegraphics[height=27mm]{example-image-b} \\\hline
\includegraphics[height=27mm]{example-image-a}
\includegraphics[height=27mm]{example-image-b} \\\noalign{\smallskip} \hline \noalign{\smallskip}
$\varphi =0.5, 126\si{\meter\per\second}$ \\ \noalign{\smallskip} \hline
\end{tabular}
\end{center}
\end{document}

You can also remove that space on a row basis by adding \\[-\dp\strutbox] at the end of row. All credits to egreg for \dp\strutbox.

\documentclass{article}
\usepackage{graphicx}
\usepackage{siunitx}
\sisetup{per-mode=symbol}
\begin{document}
\begin{center}
\setlength{\tabcolsep}{0pt}
\begin{tabular}{|c|}
\hline
\includegraphics[height=27mm]{example-image-a}
\includegraphics[height=27mm]{example-image-b} \\[-\dp\strutbox]\hline
\includegraphics[height=27mm]{example-image-a}
\includegraphics[height=27mm]{example-image-b} \\ \hline
$\varphi =0.5, 126\si{\meter\per\second}$ \\ \hline
\end{tabular}
\end{center}
\end{document}

-
Thanks! It works! But how can I apply this only for a sertain row. Because the row with explanation (phi=0.5, V=120m/s ...) must stay normal. –  user112 Aug 8 '14 at 10:39
@user112 See the updated answer. But it is little bit hacky. –  Harish Kumar Aug 8 '14 at 11:02
Thanks, that works, but when I do this, the table/cell border (vertical frame) is teared in cells where \noalign{\smallskip} is applied. =) –  user112 Aug 8 '14 at 13:33
@user112 I have added some method. But you may be better of with egreg's technique :-) –  Harish Kumar Aug 9 '14 at 0:17