\documentclass{article}

\usepackage[font=small]{caption}
\usepackage{subcaption}

\pagestyle{empty}

\begin{document}

\begin{figure}
  \begin{subfigure}[b]{.5\linewidth}
    \centering\Large A
    \caption{A subfigure}\label{fig:1a}
  \end{subfigure}%
  \begin{subfigure}[b]{.5\linewidth}
    \centering\Large B
    \caption{Another subfigure}\label{fig:1b}
  \end{subfigure}
  \caption{Example figure containing subfigures}\label{fig:1}
\end{figure}

\end{document}
