Inserting horizontal space between two images in the `figure` environment

Question

I want to place three figures next to each other, as indicated in the code below. But the resulting image has all three figures packed very closely to one another. I'd like to have some horizontal separation between the images. How do I modify the code below to achieve that?

\begin{figure}[ht]
  \centering
  \includegraphics[width=5cm]{./miscimages/1nng-example.png}
  \includegraphics[width=5m]{./miscimages/2nng-example.png}
  \includegraphics[width=5cm]{./miscimages/3nng-example.png}
  \caption{\label{fig:knng} Generating some graphs}
\end{figure}

Answer 1

    \begin{figure}[ht]
    \centering
    \includegraphics[width=5cm]{./miscimages/1nng-example.png}\hfill
    \includegraphics[width=5mm]{./miscimages/2nng-example.png}\hfill
    \includegraphics[width=5cm]{./miscimages/3nng-example.png}
    \caption{\label{fig:knng} Generating some graphs}
\end{figure}

\begin{figure}[ht]
    \centering
    \includegraphics[width=5cm]{./miscimages/1nng-example.png}\hspace{4ex}
    \includegraphics[width=5mm]{./miscimages/2nng-example.png}\hspace{4ex}
    \includegraphics[width=5cm]{./miscimages/3nng-example.png}
    \caption{\label{fig:knng} Generating some graphs}
\end{figure}