  We explore the influence of the axion-plasmon on the optical properties of
the charged black hole and show how the axion-plasmon coupling modifies the
motion of photons around the charged black hole. We then explore in details
observational effects such as the black hole shadow, the gravitational
deflection angle, Einstein rings and shadow images obtained by radially
infalling gas on a black hole within a plasma medium. An important finding is
that the intensity of the electromagnetic radiation increases with the increase
of charge and the size of the black hole shadow decreases with increase of the
electric charge for a fixed axion-plasmon coupling values when observed from
sufficiently large distance. Overall, for a constant value of charge the
optical appearance of the black hole shadow depends on the surrounding plasma
model and the largest shadow radius if found for the case of no plasma, while
the smallest shadow radius is found for the case of homogeneous plasma.
