  Thanks to unparalleled near-horizon images of the shadows of Messier 87*
(M87*) and Sagittarius A* (Sgr A*) delivered by the Event Horizon Telescope
(EHT), two amazing windows opened up to us for the strong-field test of the
gravity theories as well as fundamental physics. Information recently published
from EHT about the Sgr A*'s shadow lets us have a novel possibility of
exploration of Lorentz symmetry violation (LSV) within the Standard-Model
Extension (SME) framework. Despite the agreement between the shadow image of
Sgr A* and the prediction of the general theory of relativity, there is still a
slight difference which is expected to be fixed by taking some fundamental
corrections into account. We bring up the idea that the recent inferred shadow
image of Sgr A* is explicable by a minimal SME-inspired Schwarzschild metric
containing the Lorentz violating (LV) terms obtained from the post-Newtonian
approximation. The LV terms embedded in Schwarzschild metric are dimensionless
spatial coefficients ${\bar s}^{jk}$ associated with the field responsible for
LSV in the gravitational sector of the minimal SME theory. In this way, one can
control Lorentz invariance violation in the allowed sensitivity level of the
first shadow image of Sgr A*. Actually, using the bounds released within
$1\sigma$ uncertainty for the shadow size of Sgr A* and whose fractional
deviation from standard Schwarzschild, we set upper limits for the two
different combinations of spatial diagonal coefficients and the time-time
coefficient of the SME, as well. The best upper bound is at the $10^{-2}$
level, which should be interpreted differently from those constraints
previously extracted from well-known frameworks since unlike standard SME
studies it is not obtained from a Sun-centered celestial frame but comes from
probing the black hole horizon scale.
