def get_max_size(image_list):
    """ Calculate the maximum height and width of all images in image_list. 

        Parameters
        ----------
        image_list : list
            List of images
    """
    width_max = 0;
    height_max = 0;
    for image in image_list:
        image_size = image.size
        width_max = max(image_size[0],width_max)
        height_max = max(image_size[1],height_max)
    return width_max, height_max