In earlier work, Tu and Adams proposed the ERDED method, an effective technique for generating triangle-mesh models of digital images through explicit representation of discontinuities. In this paper, we propose a modified version of the ERDED method that generates a triangle mesh which better approximates the original image using an optimization-based algorithm. The proposed method is shown to produce image approximations of higher quality than those obtained by the ERDED method, both in terms of squared error and subjective quality. Moreover, this improvement in quality comes at a relatively modest computational cost, with the proposed method typically taking only a few seconds of computation time.