Electrical tomography is the reconstruction of an image of the interior of a body, based on measurements made on its surface. Mathematically it can be described as a coefficient inverse problem for the Laplace equation, written in the divergent form. The coefficient is a function of the space variables and characterizes the electrical properties of the medium. One of the best-known and most developed approaches is electrical capacitance tomography (ECT). This method has some advantages, but because of the non-linear structure of the mathematical model, the results of the regularization procedures for image reconstruction are not perfect. We propose here a fast post-processing algorithm to improve the quality of the electrical tomography images, obtained by any method. This algorithm is based on the explicit splineapproximation method theoretically justified for restoring some classes of functions. Numerical experiments on simulated model problems confirm its good properties.