Nonlinear transformation of one image plane relative to another by spatially constrained elastic matching of two pixel grids is proposedas a technique of measuring image similarity for the purpose of featureless face identification. The elastic matching algorithm is devised as a combination of two dynamic programming procedures applied independently to each row and then to each column of the pixel grid. In contrast to the commonly adopted method of measuring face image similarity based on the dynamic link architecture, the proposed method is non-iterative and it avoids image segmentation. Most importantly the method provides the linear computational complexity with respect to the number of pixels without application of parallel computers.