# Horizontally align figures using parbox

I have 6 images and I need to align them in a 2x3 matrix with 3 images on 1 line and 3 on the other. This is the code so far which vertically aligns all 6 images. How do I change it?

\parbox{\columnwidth}{
\parbox{0.3\columnwidth}{
\begin{center}
\includegraphics[width=0.3\textwidth]{img/preproc_1.png}
Raw Image
\end{center}
}}
\parbox{\columnwidth}{
\parbox{0.3\columnwidth}{
\begin{center}
\includegraphics[width=0.3\textwidth]{img/preproc_2.png}
Gaussian Smoothing
\end{center}
}}
\parbox{\columnwidth}{
\parbox{0.3\columnwidth}{
\begin{center}
\includegraphics[width=0.3\textwidth]{img/preproc_3.png}
Eigenvalues
\end{center}
}}
\parbox{\columnwidth}{
\parbox{0.3\columnwidth}{
\begin{center}
\includegraphics[width=0.3\textwidth]{img/preproc_4.png}
Seeds
\end{center}
}}
\parbox{\columnwidth}{
\parbox{0.3\columnwidth}{
\begin{center}
\includegraphics[width=0.3\textwidth]{img/preproc_5.png}
Labeled Seeds
\end{center}
}}
\parbox{\columnwidth}{
\parbox{0.3\columnwidth}{
\begin{center}
\includegraphics[width=0.3\textwidth]{img/preproc_6.png}
Boxes
\end{center}
}}

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With your approach, you're heading in the right direction. But you define a \parbox[\columnwidth] for each of your graphics. So you explicitly tell LaTeX to put every picture on a separate line. Just remove 4 of your "big" \parboxes and it works the way you planned it to.

\documentclass[draft]{article}
\usepackage{graphicx}
\begin{document}
\parbox{\columnwidth}{
\parbox{0.3\columnwidth}{
\centering
\includegraphics[width=0.3\textwidth]{img/preproc_1.png}
Raw Image
}
\parbox{0.3\columnwidth}{
\centering
\includegraphics[width=0.3\textwidth]{img/preproc_2.png}
Gaussian Smoothing
}
\parbox{0.3\columnwidth}{
\centering
\includegraphics[width=0.3\textwidth]{img/preproc_3.png}
Eigenvalues
}}

\parbox{\columnwidth}{
\parbox{0.3\columnwidth}{
\centering
\includegraphics[width=0.3\textwidth]{img/preproc_4.png}
Seeds
}
\parbox{0.3\columnwidth}{
\centering
\includegraphics[width=0.3\textwidth]{img/preproc_5.png}
Labeled Seeds
}
\parbox{0.3\columnwidth}{
\centering
\includegraphics[width=0.3\textwidth]{img/preproc_6.png}
Boxes
}}
\end{document}


By the way, I recommend to use \centering instead of \begin{center}...\end{center} in an environment such as a \parbox. Refer to l2tabu for this and also see Should I use center or centering for figures and tables?

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