\begin{overpic}[width=0.49\textwidth]{20YJ-139}
\put(1,74){\colorbox{white}{(\sublabel{20YJ-139}) \href{http://dream.misasa.okayama-u.ac.jp/?q=20200409102918-543197}{20YJ-139}}}
%%(\subref{20YJ-139}) \href{20YJ-139}
\color{red}
\end{overpic}