  In this paper we study some features of the Reissner-Nordstr\"om metric both
from an analytic and a visual point of view. We perform an accurate ray tracing
and study of null geodesics in various situations. Among the issues we focus on
are (i) the comparison with the Schwarzschild case, (ii) the naked singularity
case, where, if the electric charge is not too large, some dark shell appears
on images despite there is no horizon in the metric, and (iii) the wormhole
crossing case, i.e., a visual exploration of the maximal analytic extension of
the metric.
