Three figures in two rows are not displayed in PDF after compilation

Question

I want to have the same alignment of figures as stated in the linked question:

(a) (b)
  (c)

I followed the exact answers given in the link with minipage and subfigure. Both of them are compiling fine. However, the PDF file do not have any of the figures. I have tried this with two Linux machines, Ubuntu and CentOS. Same result.

I am trying this in a two column document with \begin{figure}..\end{figure}.

This is my code which is not rendering any image:

\documentclass[sigconf, 10pt]{acmart}

\usepackage{tabularx}
\usepackage{graphicx}
\usepackage{caption}
\usepackage[font={footnotesize}]{subcaption}
\captionsetup[subfigure]{position=b}   
\begin{document} 
\begin{figure}[!t]
        \centering
        \begin{subfigure}[t]{0.49\columnwidth}
            \centering
            \includegraphics[width=\textwidth]{example-image-a}
            \caption{}
        \end{subfigure}\hfil
        \begin{subfigure}[t]{0.49\columnwidth}
            \centering
            \includegraphics[width=\textwidth]{example-image-b}
            \caption{}
        \end{subfigure}\newline
        \begin{subfigure}[t]{0.49\columnwidth}
            \centering
            \includegraphics[width=\textwidth]{example-image-c}
            \caption{}
        \end{subfigure}
        \caption{}
\end{figure}
\end{document}

If I change the first two subfigure sizes to 0.33\columnwidth, then it works and I can see the figures in the PDF. However, that looks bad and not what I want.

Can anybody guess or suggest what is happening? Pretty clueless at this point.

Answer 1

Your code fragment is fine. You should see figures:

If you not, than you have something in document, what you not show us. So you need always to provide MWE (Minimal Working example) which reproduce your problem and not only a code fragment. My testing MWE is:

\documentclass[twocolumn]{article}
\usepackage{graphicx}
\usepackage{subcaption}

\begin{document}
\begin{figure}[ht]
    \centering
    \begin{subfigure}[t]{0.49\linewidth}
        \includegraphics[width=\linewidth]{example-image-a}
        \caption{}
    \end{subfigure}\hfil
    \begin{subfigure}[t]{0.49\columnwidth}
        \includegraphics[width=\linewidth]{example-image-b}
        \caption{}
    \end{subfigure}

    \medskip
    \begin{subfigure}[t]{0.49\linewidth}
        \includegraphics[width=\linewidth]{example-image-c}
        \caption{}
    \end{subfigure}
    \caption{}
\end{figure}
\end{document}

Observe difference how are defined widths for the subfigure and image in above MWE and your code fragment. It also works in one column document.