%%
%% The LaTeX Companion, 3ed
%%
%% Example 7-4-15 on page I-557 in "Customizing the subcaptions".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{135.0pt}

%StartShownPreambleCommands
\usepackage{graphicx}
\newcommand\FIG[1]{\includegraphics[#1]{cat}}
\usepackage[font={scriptsize,sl},skip=3pt]{subcaption}
\captionsetup{subrefformat=parens}
%StopShownPreambleCommands

\begin{document}
\begin{figure}   \centering
 \subcaptionbox{\label{1}}{\FIG{width=3pc}}           \quad
 \subcaptionbox{\label{2}}{\FIG{angle=20,width=3pc}}  \quad
 \subcaptionbox{\label{3}}{\FIG{height=1pc,width=3pc}}
\caption[A group of cats]{A group of cats: \subref{1}
         the first cat, \subref{2} a climbing one,
         and \subref{3} one that is stretched.}
\end{figure}
\end{document}