\documentclass{article}
\usepackage{graphicx}
\begin{document}

Testing implicit inclusion of graphics files

\begin{figure}
\includegraphics{fig_testa}
\end{figure}

\begin{figure}
\includegraphics{fig_testb}
\end{figure}

\begin{figure}
\includegraphics{fig_testc}
\end{figure}

\end{document}
