\documentclass[tikz, border=0pt]{standalone}
\usepackage{graphicx}

\tikzset{
    vertex/.style = {
        circle,
        fill            = black,
        outer sep = 0pt,
        inner sep = 0pt,
    }
}
\begin{document}
\begin{tikzpicture}[border=0pt]
  \node[inner sep=0pt] (progress) at (0,0) {\includegraphics[width=1000pt]{tikz_figs/training/progress.pdf}};
  \node[inner sep=0pt] (epoch1) at (-16.3,9.3) {\includegraphics[width=50pt]{tikz_figs/training/10.png}};
  \draw [ultra thick] (-16.3,-4.9) -- (-16.3,6.2);
  \node[inner sep=0pt] (epoch2) at (-10.35,9.3) {\includegraphics[width=50pt]{tikz_figs/training/100.png}};
  \draw [ultra thick] (-10.35,-4.9) -- (-10.35,6.2);
  \node[inner sep=0pt] (epoch3) at (9.2,9.3) {\includegraphics[width=50pt]{tikz_figs/training/390.png}};
  \draw [ultra thick] (9.2,-4.9) -- (9.2,6.2);
  \node[rotate=90] (acc) at (-17.8, 0) {\LARGE Accuracy};
\end{tikzpicture}
\end{document}