  We consider necessary and sufficient conditions for photons emitted from an
arbitrary spacetime position of the extremal Kerr black hole to escape to
infinity. The radial equation of motion determines the necessary conditions for
photons emitted from $r=r_*$ to escape to infinity, and the polar angle
equation of motion further restricts the allowed region of photon motion. From
these two conditions, we provide a method to visualize a two-dimensional photon
impact parameter space that allows photons to escape to infinity, i.e., the
escapable region. Finally, we completely identify the escapable region for the
extremal Kerr black hole spacetime. This study has generalized our previous
result [K.~Ogasawara and T.~Igata, Phys. Rev. D \textbf{103}, 044029 (2021)],
which focused only on light sources near the horizon, to the classification
covering light sources in the entire region.
