\begin{overpic}[width=0.49\textwidth]{tour3}
\put(1,74){\colorbox{white}{(\sublabel{tour3}) \href{http://dream.misasa.okayama-u.ac.jp/?q=20210114061130-907780}{tour3}}}
%%(\subref{tour3}) \href{tour3}
\color{red}
\end{overpic}