To modify the aspect ratio of images in a video sequence, a measure of image energy is provided at or around each pixel, for example by taking differences between adjacent pixels. A minimum energy path of contiguous pixels is then identified which extends across the image from one edge to another, for example vertically if the width of the picture is to be modified. Information concerning the location of a path in one image is used in the identification of a path in the next image, for example by biasing the energy measure of the path. The aspect ratio of each image is then modified by removing or by replicating the minimum energy path of contiguous pixels.