1. A method for adjusting image data defining an image, the method comprising, by a data processor executing software and/or firmware instructions: generating a saliency map for the image wherein generating the saliency map comprises one or more of: assigning saliency to pixels based on the locations of the pixels in the image; and receiving information regarding the saliency of various parts of the image by way of a user interface; establishing a global transformation based on the image data wherein establishing the global transformation comprises: ignoring parts of the image data corresponding to image areas indicated by the saliency map as having low saliency; or weighing parts of the image data corresponding to image areas indicated by the saliency map as having low saliency less heavily than other parts of the image data corresponding to image areas indicated by the saliency map as having higher saliency; and one or more of: applying the global transformation to the image data to yield altered image data and displaying the altered image data on a display; applying the global transformation to the image data to yield altered image data and storing the altered image data on a non-transitory medium; and storing a definition of the global transformation on a non-transitory medium.