This paper proposes an error compensation scheme of two-dimensional (2D) convolver in which both approximate circuit- and algorithm-level techniques are utilized in the design. Truncation and voltage scaling are used as circuit techniques, while bit-width reduction is utilized at the algorithm level. These different techniques are related to the configuration of the convolver by which its operation can be configured to meet different and often contrasting figures of merit. An extensive evaluation of different error metrics is performed. An error analysis is also presented to substantiate the simulation results; an error compensation scheme is introduced to remedy a loss of accuracy in computation. Convolution for image processing is treated in detail to show the effectiveness of the proposed approach. The design, the analysis and the simulation results show that the approximate techniques utilized in the inexact convolver can operate in synergy.