  We calculate the photon sphere $r_{ph}$ and critical curve $b_c$ for the
quantum corrected Schwarzschild black hole, finding that they violate an
universal inequalities proved for asymptotically flat black holes which satisfy
null energy condition in the framework of Einstein gravity. This violation seem
to be a common phenomenon when considering quantum modification of Einstein
gravity. Furthermore, we study the shadows, lensing rings and photon rings in
the quantum corrected Schwarzschild black hole. The violation leads to a larger
bright lensing ring in the observational appearance of thin disk emission near
the black hole compared with the classical Schwarzschild black hole. Our
analysis may provide a observational evidence for quantum effect of general
relativity.
