  A search is presented for photonic signatures, motivated by generalized
models of gauge-mediated supersymmetry breaking. This search makes use of
proton-proton collision data at $\sqrt{s}$ = 13 TeV corresponding to an
integrated luminosity of 36.1 fb$^{-1}$ recorded by the ATLAS detector at the
LHC, and it explores models dominated by both strong and electroweak production
of supersymmetric partner states. Experimental signatures incorporating an
isolated photon and significant missing transverse momentum are explored. These
signatures include events with an additional photon or additional jet activity
not associated with any specific underlying quark flavor. No significant excess
of events is observed above the Standard Model prediction, and 95%
confidence-level upper limits of between 0.083 fb and 0.32 fb are set on the
visible cross section of contributions from physics beyond the Standard Model.
These results are interpreted in terms of lower limits on the masses of
gluinos, squarks, and gauginos in the context of generalized models of
gauge-mediated supersymmetry, which reach as high as 2.3 TeV for strongly
produced and 1.3 TeV for weakly produced supersymmetric partner pairs.
