  I propose classical and quantum limits to the statistical resolution of two
incoherent optical point sources from the perspective of minimax parameter
estimation. Unlike earlier results based on the Cram\'er-Rao bound, the limits
proposed here, based on the worst-case error criterion and a Bayesian version
of the Cram\'er-Rao bound, are valid for any biased or unbiased estimator and
obey photon-number scalings that are consistent with the behaviors of actual
estimators. These results prove that, from the minimax perspective, the
spatial-mode demultiplexing (SPADE) measurement scheme recently proposed by
Tsang, Nair, and Lu [Phys. Rev. X 6, 031033 (2016)] remains superior to direct
imaging for sufficiently high photon numbers.
