\epubtkImage{figure3.png}{%
\begin{figure}[h]
  \centerline{(a)\parbox[t]{5cm}{\vspace{0pt}\includegraphics[width=5cm]{figure3a}}\qquad
              (b)\parbox[t]{5cm}{\vspace{0pt}\includegraphics[width=5cm]{figure3b}}}
  \caption{A figure composed from several subfigures.}
  \label{figure:image2}
\end{figure}}