In this article, we present a generic software for the simulation of gamma-ray radiography. This software simulates the entire radiographic system, from the source to the detector consisting of metallic screens and films. In an industrial context where the goal is to detect structural flaws in material like cracks, this simulator allows to compute gamma-ray images for different system parameters. By this way, engineers can choose an optimal set of parameters leading to the best image of flaws. We use Monte-Carlo techniques for the simulation of the whole system composed of a source, an object to inspect and a detector. The main contribution of this paper is to show that simulated images are coherent with real images although we use a simplified model for particle transport. Besides, we propose an acceleration technique to simulate the Markov chain of photon transport. Finally, an experimental design is performed leading to a linear model expressing the influence of the system parameters on image quality.