  We investigate the effects of quintessence dark energy on the shadows of
black hole, surrounded by various profiles of accretions. For the thin disk
accretion, the images of the black hole comprises the dark region and bright
region, including direct emission, lensing rings and photon rings. Although
their details depend on the form of the emission, generically, the direct
emission plays a major role for the observed brightness of the black hole,
while the lensing ring makes a small contribution and photon ring makes a
negligible contribution. The existence of cosmological horizon also plays an
important role in the shadows, since the observer in the domain of outer
communications is nearby the cosmological horizon. For the spherically
symmetric accretion, the static and infalling matters are considered. We find
that the positions of photon spheres are the same for both static and infalling
accretions. However, the observed specific intensity of the image for the
infalling accretion is darker than the static accretion, due to the Doppler
effect of the infalling movement.
