RequirePackage{luatex85}
documentclass{article}
usepackage{pgfplots,caption,subcaption,mwe,showframe}

pgfplotsset{compat=newest}

begin{document}

begin{figure}
    centering
    pgfmathsetlengthmacro{myaxiswidth}{0.33textwidth-width(" 300 ")}% subtract width of widest ticklabel, with a space on each side
    begin{subfigure}[t]{0.33textwidth}
        begin{tikzpicture}
            begin{axis}[enlargelimits=false,width=myaxiswidth, height=0.3textheight, scale only axis]
                addplot graphics [xmin=0, xmax=50, ymin=0, ymax=150] {example-image-a};
            end{axis}
        end{tikzpicture}
    end{subfigure}%
    %
    begin{subfigure}[t]{0.33textwidth}
        begin{tikzpicture}
            begin{axis}[enlargelimits=false,width=myaxiswidth, height=0.3textheight, scale only axis, ytick=empty]
                addplot graphics [xmin=0, xmax=50, ymin=0, ymax=150] {example-image-b};
            end{axis}
        end{tikzpicture}
    end{subfigure}%
    %
    begin{subfigure}[t]{0.33textwidth}
        begin{tikzpicture}
            begin{axis}[enlargelimits=false,width=myaxiswidth, height=0.3textheight, scale only axis, ytick=empty]
                addplot graphics [xmin=0, xmax=50, ymin=0, ymax=150] {example-image-c};
            end{axis}
        end{tikzpicture}
    end{subfigure}
end{figure}
end{document}