A method for symmetric and inverse-consistent registration of a pair of digital images includes calculating a first update of a forward transformation of a first digital image to a second digital image from a previous update of the forward transformation and a gradient of a cost function of the first and second digital images, calculating a first update of a backward transformation of the second digital image to the first digital image from an inverse of the first update of the forward transformation, calculating a second update of the backward transformation from first update of the backward transformation and the gradient of a cost function of the second and first digital images, and calculating a second update of the forward transformation from an inverse of the second update of the backward transformation.