def get_all_coords_in_image(length_x, length_y):
    """
    Get a list of all possible coordinates, based on two numbers representing a rectangular grid

    :param length_x: horizontal size of field
    :param length_y: vertical size of field
    :returns: list of all coordinate pairs in a field of size length_x x length_y
    :raises TypeError: none
    """
    if length_x and length_y:
        new_coord_list = []
        for spot_y in range(length_y):
            for spot_x in range(length_x):
                new_coord_list.append((spot_x, spot_y))
        # print(new_coord_list)
        return new_coord_list
    else:
        return False