与图形标签对齐的文本

Question

如何添加与图形标签对齐的文本，类似于脚注（无编号）？我尝试过，但没有成功，如下图红色所示

\documentclass[12pt,a4paper]{article}
\usepackage{graphicx, caption,lipsum}

\begin{document}

\lipsum[1-1]

\begin{center}
\includegraphics[width=3cm]{example-image}
\captionof{figure}{ Image }
\end{center}

\lipsum[2-2]

\end{document}

附加图像

Answer 1

好消息是会singlelinecheck自动计算标题的宽度。但是，根据选项的不同，计算位置可能有所不同。

\documentclass[12pt,a4paper]{article}
\usepackage{graphicx, caption,lipsum}

\newcommand{\mycaption}[3][\empty]{% #1=short caption (optionsl), #2=caption, #3=text
  \ifx\empty#1\relax
    \caption[#1]{#2}%
  \else
    \caption[#1]{#2}
  \fi
  \sbox0{\figurename~\thefigure:}% compute width of line
  \sbox1{\usebox0 #2}% compute width of centered text
  \ifdim\wd1>\linewidth \wd1=\linewidth \fi% perform single line check
  \parbox{\wd1}{\raggedright\footnotesize
  \leavevmode\rlap{\raisebox{\ht\strutbox}{\rule{\wd0}{0.5pt}}}%
  #3}\par}

\begin{document}

\lipsum[1-1]

\begin{figure}[ht]% to avoid large blank spaces
\centering
\includegraphics[width=3cm]{example-image}
\mycaption{Some sort of image}{Source: Image black book}
\end{figure}

\lipsum[2-2]

\end{document}