Filter transmission curves used to simulate the images (normalised to arbitrary units) in this work. The four filters I_E, Y_E, J_E, and H_E form the Euclid set, while u, g, r, i, and z are external complementary filters (from LSST/VRO). The NIR curves are early estimates of the actual transmission functions, which are described in their latest updated version in Euclid Collaboration (2022c); however, since we only use these data to compute the input fluxes, the differences are not relevant for the present work.