In this paper we propose a new optimal partition algorithm and show applications to multilabel image classification problems. Possibly noisy and blurred greyscale and color images can be processed, with or without automatic update of the labels. Regularization is performed by a non standard approximation of the total interface length, which involves a system of uncoupled linear partial differential equations and shows $\Gamma$-converge properties in the set of characteristic functions. These good mathematical properties are recovered in the numerical convergence scheme.