The present work reports on the state of advancement of the synthetic fast camera diagnostic developed for the JOREK code (3D time-varying non-linear magnetohydrodynamic code). At present, the JOREK fast camera allows the rendering of images from 5D and 6D kinetic particle distributions using a pinhole camera model. The physical models currently implemented consist of the guiding-center [1] and full orbit [2] synchrotron radiation models. The aim of the tool is to assess the consistency of fluid and kinetic simulations of runaway electron (RE) beams performed by the JOREK code against, but not limited to, the JET experimental videos. After discussing the physical and numerical models implemented in the synthetic diagnostic, results from a first benchmark of the JOREK fast camera against the SOFT code are reported [1]. The benchmark is based on a hollow current profile MHD equilibrium capable of reproducing the hollow synchrotron radiation spot observed in JET RE experiments. After having introduced the new tool, a first application to the rendering of synchrotron images of RE beams with 3D magnetic topology is reported. The aim is to determine if the island-like features observed in the JET synchrotron videos can be attributed to the presence of magnetic islands in the RE beam. [1] M. Hoppe et al., Nucl. Fusion, vol. 58, p. 026032, 2018 [2] L. Carbajal, D. del-Castillo-Negrete, Plasma Phys. Control. Fusion, vol.59, p.124001, 2017.