I am trying to make a table which includes graphics as well.
I am doing
\documentclass[a4paper,12pt]{book}
\usepackage{array}
\begin{document}
\begin{table}[h!]
\begin{center}
\begin{tabular}{ | c | p{4cm} | p{3cm}| }
\hline
Process & Diagrams & \sum $\left| \mathcal{M} \right|^2 / \left ( 4 \pi \alpha_s\right)^2$ \\ \hline\hline
$qq^\prime \rightarrow qq^\prime$
&
\centering
\vspace{1mm}
\includegraphics[\width=0.5\textwidth, height=20mm]{./chapter3/figures_susy/qq'_qq'.png}
&
\vspace{1mm}
$\frac{4}{9} \frac{s^2+u^2}{t^2}$
\\ \hline
\end{tabular}
\label{tab:scattering_diagrams}
\end{center}
\end{table}
\end{document}
but all I get looks like this
What I want is something like this
\documentclass{...}
and ending with\end{document}
.