def to_coord_system(vertices, width, height):
    """ Changes vertices to image coordinate system (2D image)
    
    Parameters:
        vertices (ndarray): The 3D face vertices.
        width (int): The rendering width.
        height (int): The rendering height.
    
    Returns:
        ndarray: The new vertices in coordinate system.
    """
    proj_vertices = vertices.copy()

    proj_vertices[:, 0] = proj_vertices[:, 0] + width / 2
    proj_vertices[:, 1] = proj_vertices[:, 1] + height / 2
    proj_vertices[:, 1] = height - proj_vertices[:, 1] - 1
    
    return proj_vertices