Como ter várias imagens da esquerda para a direita, para cima?

Question

Basicamente eu quero ter uma figura como abaixo:

Porém, consigo colocar a esquerda para a direita, como adicionar um Up?

\documentclass{article}
\usepackage[margin=0.5in]{geometry}
\usepackage[utf8]{inputenc}
\usepackage{textcomp}
\usepackage{pgfplots}
\usepackage{subcaption}

\begin{document}


\begin{figure}[ht]
\begin{subfigure}{.5\textwidth}
  \centering
  % include first image
  \includegraphics[width=.5\linewidth]{image_file_name}  
  \caption{Put your sub-caption here}
  \label{fig:sub-first}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
  \centering
  % include second image
  \includegraphics[width=.5\linewidth]{image_file_name}  
  \caption{Put your sub-caption here}
  \label{fig:sub-second}
\end{subfigure}
\caption{Put your caption here}
\label{fig:fig}
\end{figure}

\end{document}

Minha saída atual:

Answer 1

Basta adicionar a terceira imagem... Ou estou errado em alguma coisa?

\documentclass{article}
\usepackage[margin=0.5in]{geometry}
\usepackage[utf8]{inputenc}
\usepackage{textcomp}
\usepackage{pgfplots}
\usepackage{subcaption}

\begin{document}


    \begin{figure}[ht]
        \begin{subfigure}{\textwidth}
            \centering
            % include first image
            \includegraphics[width=.25\linewidth]{example-image-a}  
            \caption{Put your sub-captionA here}
            \label{fig:sub-firstA}
        \end{subfigure}
        \begin{subfigure}{.5\textwidth}
            \centering
            % include first image
            \includegraphics[width=.5\linewidth]{example-image-b}  
            \caption{Put your sub-captionB here}
            \label{fig:sub-first}
        \end{subfigure}
        \begin{subfigure}{.5\textwidth}
            \centering
            % include second image
            \includegraphics[width=.5\linewidth]{example-image-c}  
            \caption{Put your sub-captionC here}
            \label{fig:sub-second}
        \end{subfigure}
        \caption{Put your caption here}
        \label{fig:fig}
    \end{figure}

\end{document}
\end{document}

ATUALIZAR Com menos espaço entre as imagens

\documentclass{article}
\usepackage[margin=0.5in]{geometry}
\usepackage[utf8]{inputenc}
\usepackage{textcomp}
\usepackage{pgfplots}
\usepackage{subcaption}

\begin{document}


    \begin{figure}[ht]
        \begin{subfigure}{\textwidth}
            \centering
            % include first image
            \includegraphics[width=.45\linewidth]{example-image-a}   % this width should be half of the width of the other two images
            \caption{Put your sub-captionA here}
            \label{fig:sub-firstA}
        \end{subfigure}
        \begin{subfigure}{.5\textwidth} % this sets the figure to be max half the width of the page
            \centering
            % include first image
            \includegraphics[width=.9\linewidth]{example-image-b}  % this sets the image to fill 90% of the available space -> 45% of the line width in total. 
            \caption{Put your sub-captionB here}
            \label{fig:sub-first}
        \end{subfigure}
        \begin{subfigure}{.5\textwidth}
            \centering
            % include second image
            \includegraphics[width=.9\linewidth]{example-image-c}  
            \caption{Put your sub-captionC here}
            \label{fig:sub-second}
        \end{subfigure}
        \caption{Put your caption here}
        \label{fig:fig}
    \end{figure}

\end{document}

Answer 2

Neste exemplo reduzi a largura da subfigura/legenda para a largura da imagem. Observe que a colocação \hfilentre as duas subfiguras inferiores se expande para a mesma lacuna que \centering, enquanto \hfillempurra as subfiguras até as bordas.

\documentclass{article}
\usepackage[margin=0.5in,showframe]{geometry}
\usepackage[utf8]{inputenc}
\usepackage{textcomp}
\usepackage{pgfplots}
\usepackage{subcaption}

\begin{document}

\begin{figure}[ht]
\centering
\begin{subfigure}{.45\textwidth}
  \includegraphics[width=\linewidth]{example-image-a}  
  \caption{Put your sub-caption here}
  \label{fig:sub-first}
\end{subfigure}% ending a line with a brace adds a space
\vspace{\floatsep}% space added between consecutive floats

\begin{subfigure}{.45\textwidth}
  \includegraphics[width=\linewidth]{example-image-b}  
  \caption{Put your sub-caption here}
  \label{fig:sub-secon}
\end{subfigure}\hfil
\begin{subfigure}{.45\textwidth}
  \includegraphics[width=\linewidth]{example-image-c}  
  \caption{Put your sub-caption here}
  \label{fig:sub-third}
\end{subfigure}
\caption{Put your caption here}
\label{fig:fig}
\end{figure}

\end{document}