  In this paper, the shadows cast by Einstein-Maxwell-Dilaton-Axion black hole
and naked singularity are studied. The shadow of a rotating black hole is found
to be a dark zone covered by a deformed circle. For a fixed value of the spin
$a$, the size of the shadow decreases with the dilaton parameter $b$. The
distortion of the shadow monotonically increases with $b$ and takes its maximal
when the black hole approaches to the extremal case. Due to the optical
properties, the area of the black hole shadow is supposed to equal to the
high-energy absorption cross section. Based on this assumption, the energy
emission rate is investigated. For a naked singularity, the shadow has a dark
arc and a dark spot or straight, and the corresponding observables are
obtained. These results show that there is a significant effect of the spin $a$
and dilaton parameter $b$ on these shadows. Moreover, we examine the
observables of the shadow cast by the supermassive black hole at the center of
the Milky Way, which is very useful for us to probe the nature of the black
hole through the astronomical observations in the near future.
