subfigure latex

% Side-by-side subfigures

\usepackage{subcaption}

\begin{figure}[h]
    \begin{subfigure}{0.5\textwidth}
        \includegraphics[width=0.9\linewidth]{image1}
        \caption{Caption1}
        \label{fig:sub1}
    \end{subfigure}
    \begin{subfigure}{0.5\textwidth}
        \includegraphics[width=0.9\linewidth]{image2}
        \caption{Caption2}
        \label{fig:sub2}
    \end{subfigure}
    \caption{Subfigures}
    \label{fig:Figure1}
\end{figure}

\usepackage{caption}
\usepackage{subcaption}
\begin{document}
\begin{figure}
\begin{subfigure}{.5\textwidth}
  \centering
  % include first image
  \includegraphics[width=.8\linewidth]{log_demo1.png}  
  \caption{Put your sub-caption here}
  \label{fig:sub-first}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
  \centering
  % include second image
  \includegraphics[width=.8\linewidth]{log_demo2.png}  
  \caption{Put your sub-caption here}
  \label{fig:sub-second}
\end{subfigure}

\newline

\begin{subfigure}{.5\textwidth}
  \centering
  % include third image
  \includegraphics[width=.8\linewidth]{log_demo1.png}  
  \caption{Put your sub-caption here}
  \label{fig:sub-third}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
  \centering
  % include fourth image
  \includegraphics[width=.8\linewidth]{log_demo2.png}  
  \caption{Put your sub-caption here}
  \label{fig:sub-fourth}
\end{subfigure}
\caption{Put your caption here}
\label{fig:fig}
\end{figure}