% pandoc -f latex -t html5 --quiet
\begin{figure}[ht]
    \begin{subfigure}{0.45\textwidth}
        \centering
        \includegraphics{img1.jpg}
        \caption{Caption 1}
    \end{subfigure}

    \begin{subfigure}{0.45\textwidth}
        \centering
        \includegraphics{img2.jpg}
        \caption{Caption 2}
    \end{subfigure}
    \caption{Subfigure with Subfloat}
\end{figure}
^D

<figure>
<img src="img1.jpg" alt="Caption 1" /><figcaption>Caption 1</figcaption>
</figure>

<figure>
<img src="img2.jpg" alt="Caption 2" /><figcaption>Caption 2</figcaption>
</figure>

% pandoc -f latex -t html5
\begin{figure}[ht]
    \includegraphics{img1.jpg}
    \caption{Caption 3}
\end{figure}
^D
<figure>
<img src="img1.jpg" alt="Caption 3" /><figcaption>Caption 3</figcaption>
</figure>