beginfigure centering beginminipagec048textwidth centering includegraphicsheight=02textheight总png subcaption endminipage beginminipagec048textwidth centerin

要为图片添加边框，可以使用\fbox命令将图片包裹在一个框中。修改代码如下：

\begin{figure}
    \centering
    \begin{minipage}[c]{0.48\textwidth}
        \centering
        \fbox{\includegraphics[height=0.2\textheight]{总.png}}
        \subcaption{} 
    \end{minipage} 
    \begin{minipage}[c]{0.48\textwidth} 
        \centering 
        \fbox{\includegraphics[height=0.2\textheight]{总 (2).png}}
        \fbox{\includegraphics[height=0.2\textheight]{总 (3).png}}
        \fbox{\includegraphics[height=0.2\textheight]{总 (4).png}}
        \fbox{\includegraphics[height=0.2\textheight]{总 (5).png}}
        \fbox{\includegraphics[height=0.2\textheight]{总 (6).png}}
        \fbox{\includegraphics[height=0.2\textheight]{总 (7).png}}
        \subcaption{} 
    \end{minipage} 
    \caption{恢复后（b）分割前（a）的文档} 
\end{figure}

这样，每个图片都会被一个带有边框的框包围起来