\begin{overpic}[width=0.49\textwidth]{tour-04}
\put(1,74){\colorbox{white}{(\sublabel{tour-04}) \href{http://dream.misasa.okayama-u.ac.jp/?q=20210113032124-089832}{tour-04}}}
%%(\subref{tour-04}) \href{tour-04}
\color{red}
\end{overpic}