\begin{overpic}[width=0.49\textwidth]{tour6} \put(1,74){\colorbox{white}{(\sublabel{tour6}) \href{http://dream.misasa.okayama-u.ac.jp/?q=20210114062012-906260}{tour6}}} %%(\subref{tour6}) \href{tour6} \color{red} \end{overpic}