\enspace & \quad & \qquad ¶Synopsis, one of:
\enspace \quad \qquad
Insert a horizontal space of 1/2em, 1em, or 2em. The em is a length defined by a font designer, often thought of as being the width of a capital M. One advantage of describing space in ems is that it can be more portable across documents than an absolute measurement such as points (see Lengths/em).
This puts a suitable gap between two graphics.
\begin{center}
\includegraphics{womensmile.png}%
\qquad\includegraphics{mensmile.png}
\end{center}
See Spacing in math mode, for \quad and \qquad. These
are lengths from centuries of typesetting and so may be a better choice
in many circumstances than arbitrary lengths, such as you get with
\hspace.