Graphical representation of the detector response matrices for three different collision systems: \pp (a), \pPb (b) and \Pbp (c). The reconstructed and true photon multiplicities are denoted as $N_{\gamma\text-\rm like}$ and $N_{\gamma\text-\rm true}$, respectively, obtained from simulations using PYTHIA 8 with the Monash 2013 tune for \pp collisions and \hijing for \pPb and \Pbp collisions.