In this paper, a discrete image flux conduction equation which is completely new in this field is proposed. The new approach starts with formulating a discrete image flux conduction equation based on the concept of heat conduction theory. Based on this discrete equation, the status change at a time point can be directly computed from its spatial neighborhood. To more accurately estimate an image flux, we have used an orthogonal wavelet basis to approximate the gradient of the intensity at each point. Since the proposed approach is discrete by nature, it is not necessary to formulate a continuous PDE to fit the discrete image data set. Furthermore, introduction of different numerical methods to solve the PDE can also be avoided. Since the proposed approach does not require that a PDE be solved, it is therefore more efficient and accurate than the conventional methods. Experimental results obtained using both synthetic signals and real images have demonstrated that the proposed model could effectively handle the selective image smoothing problem.