Seismic image flattening produces subsurface images in which sedimentary layering is horizontal. With flattened images, interpretation of stratigraphic features is straightforward, and horizon picking is trivial. Most flattening methods are limited to vertical shearing and stretching of an image. Because of this limitation, these methods may have difficulty flattening seismic images that contain non-vertical deformations without significantly distorting image features. We propose a new image flattening method that uses a vector shift field, instead of a scalar field of vertical shifts, to represent deformation in an image. The method can flatten by vertically shearing or by rotating portions of an image, or by a combination of vertical shear and rotation. Because it is not limited to vertical shearing, the method can flatten in ways more consistent with geologic deformation.